Self-unlocking and energy recovery suspension control method and system and automobile suspension

Abstract

The embodiment of the application provides a suspension control method and system and an automobile suspension, and relates to the technical field of automobile suspensions.The method comprises the following steps: obtaining an axial force change rate of a screw rod, an angular velocity of a motor rotor and a back electromotive force of a motor stator;calculating a self-locking index based on the axial force change rate, the angular velocity and the back electromotive force;in the case where the self-locking index is greater than a preset self-locking threshold, driving the motor rotor and the screw rod to relatively rotate based on a preset micro-motion torque pulse, and judging whether the axial locking between the screw rod and the motor rotor is removed;in the case where the locking is removed, the micro-motion torque pulse is disconnected, and the motor rotor and the motor stator are controlled to enter an energy recovery mode.Thus, the static friction jamming state is identified through the self-locking index, the micro-motion torque pulse is immediately applied after the impact occurs to actively remove the self-locking of the screw rod and the motor rotor, the suspension is compressed to absorb the impact, and energy recovery is performed through motor power generation, so that the safety hidden danger of the suspension jamming is reduced.

Description

Technical Field

[0001] This invention relates to the field of automotive suspension control technology, and more specifically, to a suspension control method, system, and automotive suspension with self-unlocking and energy recovery. Background Technology

[0002] As the automotive industry rapidly advances towards electrification and intelligentization, suspension systems have evolved from passive suspension to semi-active suspension to active suspension. Active suspension can proactively adjust the damping force or apply dynamic force to the shock absorbers based on road conditions and vehicle driving status, thereby achieving a dynamic balance between handling stability and ride comfort. Among the various active suspension technologies, electromechanical active suspension is gradually becoming the mainstream choice for high-end vehicles due to its advantages such as fast response and energy recovery.

[0003] Electromechanical active suspension typically uses a ball screw as the transmission medium between linear and rotational motion. Specifically, the ball screw nut is connected to the motor rotor, and the screw shaft is connected to the lower control arm of the wheel. When the wheel experiences a vertical impact from an uneven road surface, the impact force pushes the screw shaft upwards in the form of a linear force, forcing the nut and motor rotor to rotate in the opposite direction, thereby absorbing the vibration. During this process, the motor can act as a generator to provide damping force, while simultaneously converting the mechanical kinetic energy generated by road bumps into electrical energy for recovery.

[0004] However, under heavy load conditions, the static friction coefficient between the nut and the motor rotor increases dramatically. When the vehicle travels over speed bumps or potholes, the axial impact force on the motor rotor increases. In the initial tens of milliseconds after the impact, due to the static friction dead zone, the nut and motor rotor completely lock up, and the entire shock absorber becomes rigid, leading to complete jamming. The impact and vibration from the road surface cannot be absorbed by the suspension and are directly transmitted to the vehicle body and passengers, potentially creating safety hazards. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a suspension control method, system and automobile suspension with self-unlocking and energy recovery, so as to solve the technical problem that the nuts and motor rotor are completely locked, the shock absorbers are completely stuck, the impact and vibration of the road surface cannot be absorbed by the suspension and are directly transmitted to the vehicle body and passengers, which can easily cause safety hazards.

[0006] To achieve the above objectives, in a first aspect, embodiments of the present invention provide a suspension control method with self-unlocking and energy recovery, applied to an automotive suspension. The automotive suspension includes a lead screw, a motor rotor, and a motor stator, wherein the lead screw and the motor rotor are threadedly connected. The method includes: acquiring the axial force change rate of the lead screw, the angular velocity of the motor rotor, and the back electromotive force of the motor stator; calculating a self-locking index based on the axial force change rate, the angular velocity, and the back electromotive force; when the self-locking index is greater than a preset self-locking threshold, driving the motor rotor and the lead screw to rotate relative to each other based on a preset micro-torque pulse, and determining whether the axial lock between the lead screw and the motor rotor is released; when the axial lock between the lead screw and the motor rotor is released, disconnecting the preset micro-torque pulse, and controlling the motor rotor and the motor stator to enter an energy recovery mode.

[0007] In this embodiment, a self-locking index is calculated by comprehensively considering the axial force change rate of the lead screw, the angular velocity of the motor rotor, and the back electromotive force of the motor stator. This self-locking index is then compared with a preset self-locking threshold to determine whether the axial lock between the lead screw and the motor rotor has been released. If the axial lock is released, the motor rotor and motor stator are controlled to enter an energy recovery mode. Thus, by determining that the motor rotor and lead screw are stuck using the self-locking index, the motor rotor is driven to rotate under a preset micro-torque pulse. This allows the suspension to release the static friction between the lead screw and motor rotor immediately upon impact, causing relative rotation between them. This allows for energy recovery through motor rotor reversal while simultaneously absorbing road impacts and vibrations, reducing safety hazards.

[0008] In some embodiments, calculating the self-locking index based on the axial force change rate, the angular velocity, and the back electromotive force includes: constructing an index term within a preset sliding time window based on the angular velocity and the back electromotive force; weighting the axial force change rate based on the index term to obtain a weighted axial force change rate; integrating the weighted axial force change rate within the preset sliding time window to obtain the self-locking index; wherein, when the motor rotor angular velocity and the back electromotive force tend to zero, the index term tends to one; when the motor rotor angular velocity and the back electromotive force are not zero, the index term tends to zero.

[0009] With this setup, when the angular velocity and back EMF approach zero, it indicates that the motor rotor is locked by static friction and cannot rotate. At this time, the exponent term approaches one to accurately capture the moment of jamming. When the angular velocity and back EMF are not zero, it indicates that the motor rotor is still rotating normally in response to changes in force. At this time, the exponent term approaches zero to accurately capture that the motor rotor and lead screw are not jammed, thereby filtering out false triggering under low-frequency, high-load conditions such as vehicle cornering and slow undulation road surfaces.

[0010] In some embodiments, constructing an exponential term within a preset sliding time window based on the angular velocity and the back electromotive force includes: squaring the angular velocity and the back electromotive force respectively and adding them together to obtain a sum of squares; multiplying the sum of squares by a preset weighting coefficient and taking the negative value to obtain an exponential value; and obtaining the exponential term based on the exponential value and the base of the natural logarithm.

[0011] This configuration, by constructing an exponential term, utilizes the nonlinear decay characteristics of the exponential function to produce a significant change in the suppressing effect when only small changes occur in angular velocity and back electromotive force, thereby improving the sensitivity to jamming between the lead screw and the motor rotor.

[0012] In some embodiments, the rate of change of axial force on the lead screw is obtained by differentiating the axial force on the lead screw. The step of driving the motor rotor to rotate relative to the lead screw based on a preset micro-torque pulse and determining whether the axial lock between the lead screw and the motor rotor is released includes: determining the peak value of the axial force on the lead screw before triggering the preset micro-torque pulse; determining the current axial force on the lead screw after triggering the preset micro-torque pulse, calculating the force drop ratio based on the current axial force and the peak value of the axial force; and determining that the axial lock between the lead screw and the motor rotor has been released if the force drop ratio is greater than a preset drop ratio threshold.

[0013] This setting is designed so that by ensuring the force drop ratio is greater than the preset drop ratio threshold, it can be determined that the static friction on the contact surface between the lead screw and the motor rotor has been successfully converted into dynamic friction, thereby determining that the axial lock between the lead screw and the motor rotor has been released.

[0014] In some embodiments, the step of driving the motor rotor and the lead screw to rotate relative to each other based on a preset micro-torque pulse, and determining whether the axial lock between the lead screw and the motor rotor is released, includes: determining the phase current change rate of the motor stator during the process of driving the motor rotor and the lead screw to rotate relative to each other based on the preset micro-torque pulse; and determining that the axial lock between the lead screw and the motor rotor has been released when the phase current change rate changes from a positive value to a negative value; wherein, the change from a positive value to a negative value indicates that the motor rotor rotates under the drive of the preset micro-torque pulse, causing the back electromotive force to increase, and the increase in back electromotive force indicates that the axial lock between the lead screw and the motor rotor has been released.

[0015] This configuration allows the phase current change rate to change from a positive value to a negative value, thus determining that the axial lock between the lead screw and the motor rotor has been released. This transforms the unlocking determination from relying on external displacement or force sensors to directly extracting the internal electrical parameters of the motor, eliminating the need for additional external sensors and simplifying the hardware architecture without sacrificing millisecond-level control accuracy.

[0016] In some embodiments, controlling the motor rotor and the motor stator to enter the energy recovery mode includes: disconnecting the drive power output to the motor stator and recovering the electrical energy generated by the rotation of the motor rotor under the drive of the lead screw.

[0017] This configuration efficiently converts the kinetic energy dissipated as heat from bumps into electrical energy, which is then stored in the battery, thus improving the overall driving range.

[0018] Secondly, embodiments of the present invention provide a self-unlocking and energy recovery suspension control system applied to an automotive suspension. The automotive suspension includes a lead screw, a motor rotor, and a motor stator, with the lead screw and the motor rotor threadedly connected. The system includes: an acquisition module for acquiring the axial force change rate of the lead screw, the angular velocity of the motor rotor, and the back electromotive force of the motor stator; a processing module for calculating a self-locking index based on the axial force change rate, the angular velocity, and the back electromotive force; when the self-locking index is greater than a preset self-locking threshold, driving the motor rotor and the lead screw to rotate relative to each other based on a preset micro-torque pulse, and determining whether the axial lock between the lead screw and the motor rotor is released; and a recovery module for disconnecting the preset micro-torque pulse and controlling the motor rotor and the motor stator to enter an energy recovery mode when the axial lock between the lead screw and the motor rotor is released.

[0019] In some embodiments, the processing module is configured to: construct an exponential term within a preset sliding time window based on the motor rotor angular velocity and the back electromotive force; weight the rate of change of the axial force on the lead screw based on the exponential term to obtain a weighted rate of change of the axial force on the lead screw; integrate the weighted rate of change of the axial force on the lead screw within the preset sliding time window to obtain the self-locking exponent; wherein, when the motor rotor angular velocity and the back electromotive force tend to zero, the exponential term tends to one; when the motor rotor angular velocity and the back electromotive force are not zero, the exponential term tends to zero.

[0020] Thirdly, embodiments of the present invention provide an automotive suspension, the automotive suspension further comprising a lead screw, a motor rotor, a motor stator, and a controller; the lead screw is threadedly connected to the motor rotor, and the controller is used to implement the self-unlocking and energy recovery suspension control method described in the first aspect above.

[0021] In some embodiments, the motor rotor is cylindrical, the inner wall of the motor rotor has threads, and the lead screw passes through the motor rotor and is threadedly connected to the motor rotor through the threads.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A flowchart of a suspension control method with self-unlocking and energy recovery provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the suspension component control process provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the functional modules of the self-unlocking and energy recovery suspension control system provided in an embodiment of the present invention.

[0025] Icons: 1000 - Self-unlocking and energy recovery suspension control system; 1100 - Acquisition module; 1200 - Processing module; 1300 - Recovery module; 2000 - Vehicle suspension; 2100 - Integrated housing; 2200 - Motor stator; 2300 - Motor rotor; 2400 - Lead screw; 2500 - Controller. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0028] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises 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 limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0029] As described in the background section, when a vehicle is under heavy load, the static friction coefficient between the nut and the motor rotor increases dramatically. If the vehicle then encounters a speed bump or pothole, the axial impact force on the motor rotor increases. Within the first few milliseconds of the impact, due to the existence of the static friction dead zone, the nut and motor rotor completely lock up, rendering the entire shock absorber rigid and causing it to seize up completely. The impact and vibration from the road surface cannot be absorbed by the suspension and are directly transmitted to the vehicle body and passengers, potentially creating safety hazards.

[0030] Therefore, this invention provides a self-unlocking and energy recovery suspension control method applied to an automotive suspension. The automotive suspension includes a lead screw, a motor rotor, and a motor stator. The lead screw 2400 and the motor rotor are threadedly connected. (See reference...) Figure 1 and Figure 2 , Figure 1 This is a flowchart of a suspension control method with self-unlocking and energy recovery provided by an embodiment of the present invention. Figure 2This is a schematic diagram of the suspension component control process provided in an embodiment of the present invention. The self-unlocking and energy recovery suspension control method includes steps S100~S400: S100: Obtain the axial force change rate of the lead screw, the angular velocity of the motor rotor, and the back electromotive force of the motor stator.

[0031] In this embodiment, the axial force change rate of the lead screw is acquired by an axial pressure sensor installed at the bottom of the suspension actuator. The axial pressure sensor senses the axial force exerted on the actuator by the vertical impact of the road surface in real time. The controller performs real-time differential processing on the axial force signal to obtain the axial force change rate. The axial force change rate reflects the degree of impact from the road surface. When a vehicle drives over sharp protrusions such as the edge of a speed bump, the axial force change rate will spike to an extremely high value in a very short time.

[0032] The angular velocity of the motor rotor is acquired by a high-precision rotor position sensor integrated inside the motor, such as a built-in magnetic encoder; the position sensor directly measures the angular position of the motor rotor, and the controller performs differential processing on the angular position signal to obtain the angular velocity.

[0033] The back electromotive force (EMF) of the motor stator is acquired through the motor's phase current acquisition module. The controller collects the voltage and phase current signals on the motor stator coils from the phase current acquisition module and extracts or estimates the back EMF from them. The axial force change rate, angular velocity, and back EMF are calculated from three dimensions: mechanical, kinematic, and electrical. The self-locking index is calculated, which allows the controller to cross-verify the actual friction state between the lead screw and the motor rotor from multiple angles.

[0034] S200, calculates the self-locking index based on the axial force change rate, angular velocity and back electromotive force.

[0035] In this embodiment, the controller fuses the signals from the three dimensions mentioned above to calculate the self-locking index. This index characterizes whether the lead screw and motor rotor are currently in a normal, retractable state or are about to enter or have already entered the static friction extreme dead zone. The self-locking index is not simply based on a single threshold value determined by the magnitude of the force. Instead, it employs a nonlinear characteristic functional based on a sliding time window, utilizing the nonlinear decay characteristics of the exponential function to sensitively detect states where force surges and motion stagnation occur simultaneously.

[0036] Specifically, when the suspension encounters the motor rotor's normal yielding condition, even if the axial force change rate is large, the motor rotor will also generate angular velocity and back electromotive force. At this time, the exponential term will strongly suppress the contribution of the axial force change rate in the integral calculation, keeping the self-locking index at a safe low level, thereby avoiding false triggering under low-frequency, high-load conditions such as vehicle cornering and slowly undulating roads. Only when the high-frequency impact causes the lead screw and motor rotor to enter a static friction jamming state, that is, the axial force change rate spikes sharply, the angular velocity approaches zero, and the back electromotive force is at an extremely low level, when all three conditions are met simultaneously, the suppressive effect of the exponential term disappears. The self-locking index is determined by the pure integral of the axial force change rate within the sliding window, i.e., the high-frequency impulse. The self-locking index rises sharply and exceeds the preset self-locking threshold, thus accurately capturing the jamming moment with a millisecond delay.

[0037] S300. When the self-locking index is greater than the preset self-locking threshold, the motor rotor and the lead screw are driven to rotate relative to each other based on the preset micro-motion torque pulse, and it is determined whether the axial lock between the lead screw and the motor rotor is released.

[0038] In this embodiment, once the self-locking index exceeds the preset self-locking threshold, the controller determines that the lead screw and motor rotor have entered the static friction extreme dead zone. Within the extremely narrow time window before the suspension compresses and yields—that is, in the initial few milliseconds when the motor rotor and lead screw are locked—the controller immediately injects a preset micro-torque pulse into the motor stator. This preset micro-torque pulse is an extremely short reverse torque pulse, its amplitude and duration precisely calibrated. It is sufficient to drive the motor rotor to produce a very small circumferential rotational slip relative to the lead screw, but insufficient to cause the suspension to compress and yield. The physical effect of this slip is to forcibly shear and tear the microscopic protrusions formed by heavy-load cold welding on the contact surface between the lead screw and motor rotor, causing the friction state of the contact surface to instantly change from static friction to dynamic friction. The equivalent friction angle drops precipitously, and the geometric self-locking condition is completely released from the physical level. It can be understood that after the preset micro-torque pulse is injected, the controller can determine the subsequent mode switching timing by judging whether the axial lock has truly been released.

[0039] In some other embodiments, at the 0-millisecond start-up instant of capturing a road impact, the controller does not output unidirectional torque, but instead injects a very short high-frequency sinusoidal alternating current (e.g., 500Hz, lasting 2-3 milliseconds) into the motor stator. By causing the motor rotor to generate high-frequency forward and reverse micro-vibrations, the contact surface between the lead screw and the motor rotor is forcibly converted from static friction to dynamic friction, and then immediately switches to a damping relief mode.

[0040] S400: When the axial lock between the lead screw and the motor rotor is released, the preset micro-motion torque pulse is disconnected, and the motor rotor and motor stator are controlled to enter the energy recovery mode.

[0041] In this embodiment, upon determining that the axial lock between the lead screw and the motor rotor has been released, two parallel operations are performed. First, the preset micro-torque pulse previously injected into the motor stator is immediately cut off, stopping the output of drive power. Second, the motor's control mode is switched from active drive mode to energy recovery mode, also known as regenerative braking mode. In regenerative braking mode, the motor is no longer a drive consuming electrical energy, but a generator providing resistance torque. At this time, the contact state between the lead screw and the motor rotor is dynamic friction, and the vertical impact load of the road surface can smoothly push the lead screw to compress and retract. The lead screw drives the motor rotor to rotate, and the permanent magnet of the motor rotor cuts the magnetic field of the motor stator coil, generating an induced current in the coil. This electrical energy is recharged to the vehicle battery through the power converter. At the same time, the reverse electromagnetic torque generated during the power generation process acts as the electromagnetic damping force required by the suspension, absorbing the impact energy of the road surface and making the compression action of the suspension smooth and gentle.

[0042] In some embodiments, for step S200, one possible implementation of the present invention is that step S200 includes sub-steps S210~S230: S210. Construct an exponential term within a preset sliding time window based on angular velocity and back electromotive force.

[0043] In this embodiment, the controller constructs the exponential term using the real-time angular velocity and back electromotive force collected at each sampling moment, instead of pre-calculating a fixed value and applying it to all moments. The function of the exponential term is to dynamically modulate the rate of change of axial force. When the angular velocity and back electromotive force indicate that the motor rotor is rotating, the contribution of the rate of change of axial force to the self-locking exponent is suppressed to near zero; when the angular velocity and back electromotive force indicate that the motor rotor is stopped, the rate of change of axial force is not suppressed, but participates in the calculation of the self-locking exponent.

[0044] S220. The axial force change rate is weighted based on the exponential term to obtain the weighted axial force change rate.

[0045] In this embodiment, for each sampling moment within the sliding time window, the exponential term at that moment is multiplied by the axial force change rate at that moment to obtain the weighted axial force change rate. When the exponential term approaches 1, indicating a jammed condition, the axial force change rate is retained; when the exponential term approaches 0, indicating a normal condition, the axial force change rate is suppressed to near zero. The purpose of weighting is to enable the self-locking exponent to accurately distinguish between high-frequency impact jamming and normal high-load conditions. The force change rate only provides a suspected signal to be verified, while the angular velocity and back electromotive force provide evidence of whether the motor rotor is truly jammed through the exponential term. Only when both conditions are met—a drastic force change rate and the simultaneous failure of angular velocity and back electromotive force—will the weighted result have a significant value.

[0046] S230. Integrate the weighted axial force change rate within a preset sliding time window to obtain the self-locking index; wherein, when the motor rotor angular velocity and back electromotive force approach zero, the index term approaches one; when the motor rotor angular velocity and back electromotive force are not zero, the index term approaches zero.

[0047] In this embodiment, the weighted axial force change rate at all sampling moments within a preset sliding time window is accumulated and integrated to obtain the self-locking index at the current moment. The width of the preset sliding time window is set to the microsecond level to limit the time range of integration, reacting only to data changes within the most recent very short time period, and not being slowed down by historical data from seconds ago. Under normal operating conditions, the weighted axial force change rate at each sampling moment is suppressed to near zero by the exponential term, and the integration result within the sliding window remains at an extremely low level, far below the preset self-locking threshold. Under jamming conditions, the exponential term approaches 1, and the integration is transformed into a pure integration of the axial force change rate within the sliding window, i.e., a high-frequency impulse. The integration result rises sharply and instantaneously exceeds the preset self-locking threshold, thus determining that the lead screw and motor rotor have entered the static friction extreme dead zone.

[0048] For example, if and only if Breakdown of the preset self-locking threshold When the ball screw enters the static friction extreme value dead zone (i.e., rigid jamming state), it immediately triggers a preset micro-motion torque pulse to unlock.

[0049] ; In the above formula Let be the self-locking exponent at the current time t; The width of the set microsecond-level sliding time window is used to smooth high-frequency data; Time within the sliding window The axial force variation rate of the lead screw 2400 The instantaneous angular velocity of the rotor. The instantaneous rate of change of phase current. The nonlinear weight amplification factor preset for the system, e is the base of the natural logarithm. This is the exponential term.

[0050] In some embodiments, for step S210, one possible implementation of the present invention is that step S210 includes sub-steps S211~S213: S211. Squaring the angular velocity and back electromotive force respectively and then adding them together gives the sum of squares.

[0051] In this embodiment, the real-time acquired angular velocity and back electromotive force values ​​are each squared, and then the two squared values ​​are added together to obtain a comprehensive index reflecting the current activity level of the motor rotor, namely the sum of squares. The purpose of squaring each value is that any non-zero signal will be nonlinearly amplified through the squaring operation, ensuring that even if only one of the angular velocity or back electromotive force shows a slight change, the sum of squares can sensitively reflect that the motor rotor is not completely stationary. Simultaneously, the squaring operation ensures that both signals always participate in subsequent calculations with positive values, avoiding suppression failure caused by positive and negative cancellation.

[0052] S212. Multiply the sum of squares by a preset weighting coefficient and take the negative value to obtain the exponent value.

[0053] In this embodiment, the sum of squares is multiplied by a preset nonlinear weighting amplification factor, and then the product is negative to obtain a negative exponent value. Taking a negative value is crucial for achieving the suppression function, because the larger the angular velocity and back electromotive force, the larger the sum of squares, and the more negative the resulting exponent value after multiplying by the weighting factor and then taking a negative value. The more negative the exponent value, the closer the subsequent exponential calculation result with a constant e as the base approaches zero. The preset weighting factor can flexibly adjust the contribution of angular velocity and back electromotive force to the suppression intensity based on the actual mechanical characteristics of the suspension, motor parameters, and expected sensitivity requirements, without changing the overall algorithm framework.

[0054] S213. Based on the exponent value and the base of the natural logarithm, the exponent term is obtained.

[0055] In this embodiment, the exponent is calculated using the base e of the natural logarithm and the exponent value to obtain the final exponent term. Since the exponent value is negative, the range of the exponent term is limited to 0 to 1. When both the angular velocity and back electromotive force approach zero, the exponent value approaches zero, the exponent term approaches 1, the suppressive effect disappears, corresponding to the self-locking condition where the motor rotor is completely jammed. When the angular velocity and back electromotive force are not zero, the exponent value is a large negative number, the exponent term approaches zero, the rate of change of axial force is strongly suppressed, corresponding to the condition where the motor rotor rotates normally.

[0056] Furthermore, by employing an exponential function with base e, the mathematical property of the exponential function decaying nonlinearly with the change of the exponent value is utilized. This allows the exponent term to rapidly drop from close to 1 to close to zero when the angular velocity or back electromotive force changes only slightly. This ensures high sensitivity to states where a surge in force occurs simultaneously with motion stagnation, and clearly defines the boundary between normal yielding and jamming.

[0057] In some embodiments, the rate of change of axial force on the lead screw is obtained by differentiating the axial force on the lead screw. For step S300, one possible implementation of the present invention is that step S300 includes sub-steps S301~S303: S301. Before triggering the preset micro-torque pulse, determine the peak value of the axial force on the lead screw.

[0058] In this embodiment, before injecting a preset micro-torque pulse into the motor stator, the controller first latches the current peak axial force of the leadscrew. The peak axial force is the maximum axial load value borne by the leadscrew due to road impact and static friction self-locking before pulse triggering, reflecting the tightness of the cold welding of the micro-protrusions on the contact surface under static friction lock-up conditions. The purpose of latching the peak axial force is to provide a comparison benchmark for calculating the force drop after subsequent pulse injection, so as to quantitatively determine whether the load drops sharply after the preset micro-torque pulse injection by recording the load level before the preset micro-torque pulse injection.

[0059] S302. After triggering the preset micro-torque pulse, determine the current axial force on the lead screw, and calculate the force drop ratio based on the current axial force and the peak axial force.

[0060] In this embodiment, after the preset micro-torque pulse injection is completed, the controller continuously reads the real-time axial force value collected by the axial pressure sensor, compares this real-time value with the latched peak axial force value, and calculates the force drop ratio. The force drop ratio is calculated by dividing the difference between the peak value and the real-time value by the peak value. This ratio quantifies the change in axial load before and after pulse injection. The larger the drop ratio, the more thoroughly the cold welding of the micro-protrusions on the contact surface is sheared, and the more complete the conversion from static friction to dynamic friction.

[0061] S303. When the force drop ratio is greater than the preset drop ratio threshold, it is determined that the axial lock between the lead screw and the motor rotor has been released.

[0062] In this embodiment, the preset drop ratio threshold is calibrated based on the actual difference between the static friction coefficient and the dynamic friction coefficient, and is typically set between 5% and 15%. When the force drop ratio exceeds the preset drop ratio threshold, the controller determines that the cold welding of the micro-protrusions on the contact surface has been successfully sheared, the equivalent friction angle has dropped sharply, and the axial lock between the lead screw and the motor rotor has been released. Since the suspension changes from rigid locking to retractable at the moment of self-lock release, the axial force originally accumulated on the lead screw will inevitably experience a sharp drop, and the force drop ratio objectively reflects the degree of unlocking completion.

[0063] For example, before injecting the preset micro-torque pulse, the controller latches the current peak axial force F1. After the preset micro-torque pulse is injected, if the force drop ratio F(t) satisfies: (F1-F(t)) / F1> ; (in, This is a preset drop ratio threshold calibrated based on the difference between static and dynamic friction coefficients, typically between 5% and 15%. Once the drop ratio exceeds this dynamic value, the rigid jam is considered to have been released.

[0064] In some embodiments, for step S300, one possible implementation of the present invention is that step S300 includes sub-steps S304~S305: S304. Based on the preset micro-motion torque pulse, determine the phase current change rate of the motor stator during the relative rotation of the motor rotor and the lead screw.

[0065] In this embodiment, during the injection of a preset micro-torque pulse, the controller acquires the phase current signal in the motor stator coil in real time through the phase current acquisition module and calculates the rate of change of the phase current over time. When the lead screw and the motor rotor are in a static friction lock-up state, the motor rotor cannot rotate, the back electromotive force approaches zero, and the injected pulse drive voltage causes the phase current to rise continuously, keeping the rate of change of the phase current positive. When the preset micro-torque pulse successfully shears the micro-protrusion cold weld, the motor rotor begins to rotate, and the back electromotive force is generated instantaneously, offsetting part of the drive voltage in the opposite direction. This causes the upward trend of the phase current to be interrupted instantaneously, and the rate of change of the phase current changes from a positive value to a negative value.

[0066] S305. When the phase current change rate changes from a positive value to a negative value, it is determined that the axial lock between the lead screw and the motor rotor has been released; wherein, the change from a positive value to a negative value in the phase current change rate indicates that the motor rotor rotates under the drive of a preset micro-torque pulse, resulting in an increase in back electromotive force, and the increase in back electromotive force indicates that the axial lock between the lead screw and the motor rotor has been released.

[0067] In this embodiment, the controller monitors the directional change of the phase current rate of change during pulse injection. A change from a positive to a negative value in the phase current rate of change indicates that the motor rotor has rotated under the drive of a preset micro-torque pulse, thereby increasing the back electromotive force (EMF) from almost zero to a measurable value. This increase in back EMF means that the permanent magnets of the motor rotor have been displaced relative to the motor stator coils; that is, the motor rotor has disengaged from its stuck position and begun to rotate automatically. This allows the axial locking between the lead screw and the motor rotor to be determined based on the sign change of the phase current rate of change and the increase in back EMF.

[0068] In some embodiments, for step S400, one possible implementation of the present invention is that step S400 includes sub-step S401: S401. Disconnect the drive power output to the motor stator and recover the electrical energy generated by the rotation of the motor rotor under the drive of the lead screw.

[0069] In this embodiment, after the unlocking determination is successful, the controller performs a drive power cut-off operation, completely canceling the torque pulse previously injected to break the static friction self-lock, causing the motor stator to exit the active torque output state. Subsequently, the motor stator enters the power generation state, and the motor rotor continues to rotate under the drive of the lead screw, cutting the magnetic field of the motor stator coil to generate an induced current, which is then recovered into the vehicle battery.

[0070] In some embodiments, if the vehicle power battery is fully charged and cannot receive feedback current, the controller will switch the motor into pure power generation mode after recognizing that the self-lock has been released. However, the generated power will not be recharged to the battery, but will be directly conducted to the discharge resistor outside the actuator and converted into heat dissipation.

[0071] In some other embodiments, instead of using pressure sensors that directly measure force, high-frequency acceleration sensors are installed on the control arms or steering knuckles under the wheels. When the wheel travels over a bumpy road surface and experiences a sudden upward transient acceleration, the controller converts this into an equivalent impact excitation force, which serves as a prerequisite for triggering unlocking.

[0072] In some other embodiments, the vehicle's standard suspension height sensor is used to perform first- or second-order differential processing on its displacement signal to extract the initial velocity or acceleration change characteristics of suspension compression, thereby replacing the impact warning of physical mechanical sensors.

[0073] In some other embodiments, instead of extracting the back electromotive force of the motor or the angle of the built-in encoder, a high-precision linear displacement sensor (or linear Hall element) is installed on the damper push rod. When the controller applies an unlocking pulse, as long as the push rod produces a micron-level actual yielding displacement, it is determined that the geometric self-locking has been released, triggering the switching of the damping power generation mode.

[0074] Based on the above method, embodiments of the present invention also provide a system corresponding to the above method, such as... Figure 3 As shown, Figure 3 This is a functional block diagram of the self-unlocking and energy recovery suspension control system provided in an embodiment of the present invention. It should be noted that the basic principle and technical effects of the self-unlocking and energy recovery suspension control system 1000 provided in this embodiment are the same as those in the above method embodiments. For the sake of brevity, parts not mentioned in this embodiment can be referred to the corresponding content in the method embodiments.

[0075] In this embodiment, the self-unlocking and energy recovery suspension control system 1000 is applied to the vehicle suspension 2000. The vehicle suspension 2000 includes a lead screw 2400, a motor rotor 2300, and a motor stator 2200. The lead screw 2400 and the motor rotor 2300 are threadedly connected. The self-unlocking and energy recovery suspension control system 1000 includes an acquisition module 1100, a processing module 1200, and a recovery module 1300.

[0076] The acquisition module 1100 is used to acquire the axial force change rate of the lead screw 2400, the angular velocity of the motor rotor 2300, and the back electromotive force of the motor stator 2200. It can be understood that the acquisition module 1100 is used to perform the above step S100.

[0077] The processing module 1200 is used to calculate the self-locking index based on the axial force change rate, angular velocity, and back electromotive force. When the self-locking index is greater than a preset self-locking threshold, it drives the motor rotor 2300 and the lead screw 2400 to rotate relative to each other based on a preset micro-motion torque pulse, and determines whether the axial lock between the lead screw 2400 and the motor rotor 2300 has been released. It can be understood that the processing module 1200 is used to execute the above steps S200~S300.

[0078] The energy recovery module 1300 is used to disconnect the preset micro-torque pulse and control the motor rotor 2300 and motor stator 2200 to enter the energy recovery mode when the axial lock between the lead screw 2400 and the motor rotor 2300 is released. It can be understood that the energy recovery module 1300 is used to perform the above step S400.

[0079] In some embodiments, the processing module 1200 is used to construct an exponential term based on angular velocity and back electromotive force within a preset sliding time window; weight the axial force change rate based on the exponential term to obtain a weighted axial force change rate; integrate the weighted axial force change rate within the preset sliding time window to obtain a self-locking exponent; wherein, when the angular velocity and back electromotive force of the motor rotor 2300 approach zero, the exponential term approaches one; when the angular velocity and back electromotive force of the motor rotor 2300 are not zero, the exponential term approaches zero. It can be understood that the processing module 1200 is used to perform the above steps S210~S230.

[0080] In some embodiments, the processing module 1200 is used to square the angular velocity and the back electromotive force respectively and then add them together to obtain a sum of squares; multiply the sum of squares by a preset weighting coefficient and take the negative value to obtain the exponent value; and obtain the exponent term based on the exponent value and the base of the natural logarithm. It can be understood that the processing module 1200 is used to perform the above steps S211~S213.

[0081] In some embodiments, the rate of change of axial force on the lead screw 2400 is obtained by differentiating the axial force on the lead screw 2400. The processing module 1200 is used to determine the peak value of the axial force on the lead screw 2400 before triggering a preset micro-torque pulse; after triggering the preset micro-torque pulse, it determines the current axial force on the lead screw 2400, calculates the force drop ratio based on the current axial force and the peak value of the axial force; if the force drop ratio is greater than a preset drop ratio threshold, it determines that the axial lock between the lead screw 2400 and the motor rotor 2300 has been released. It can be understood that the processing module 1200 is used to perform the above steps S301 to S303.

[0082] In some embodiments, the processing module 1200 is used to determine the phase current change rate of the motor stator 2200 during the relative rotation of the motor rotor 2300 and the lead screw 2400 based on a preset micro-torque pulse; when the phase current change rate changes from a positive value to a negative value, it is determined that the axial lock between the lead screw 2400 and the motor rotor 2300 has been released; wherein, the change from a positive value to a negative value of the phase current change rate indicates that the motor rotor 2300 rotates under the drive of the preset micro-torque pulse, resulting in an increase in back electromotive force, and the increase in back electromotive force indicates that the axial lock between the lead screw 2400 and the motor rotor 2300 has been released. It can be understood that the processing module 1200 is used to perform the above steps S304~S305.

[0083] In some embodiments, the recovery module 1300 is used to disconnect the drive power output to the motor stator 2200 and recover the electrical energy generated by the rotation of the motor rotor 2300 under the drive of the lead screw 2400. It can be understood that the recovery module 1300 is used to perform the above-described step S401.

[0084] Based on the same inventive concept disclosed above, correspondingly, the embodiments of the present invention also provide an automotive suspension 2000 for which the above method is applied, such as... Figure 2 As shown, the vehicle suspension 2000 also includes a lead screw 2400, a motor rotor 2300, a motor stator 2200, and a controller 2500; the lead screw 2400 is threadedly connected to the motor rotor 2300, and the controller 2500 is used to implement the above-mentioned suspension control method of self-unlocking and energy recovery.

[0085] In some embodiments, the motor rotor 2300 is cylindrical, the inner wall of the motor rotor 2300 has threads, and the lead screw 2400 passes through the motor rotor 2300 and is threadedly connected to the motor rotor 2300 through the threads.

[0086] For example, the motor stator 2200 is fixed inside the integrated housing 2100. The motor rotor 2300 is a permanent magnet rotor with a hollow sleeve structure. The inner cylindrical surface of the rotor 2300 has the inner helical raceway of the lead screw 2400 directly machined, so that the motor rotor 2300 also acts as the nut of the lead screw 2400, achieving a high degree of integration between the motor rotor 2300 and the nut. This coaxial integrated configuration eliminates intermediate transmission links such as synchronous belts or reduction gears in traditional parallel shaft arrangements, reduces the equivalent rotational inertia of rotating components to the lowest physical limit, greatly reduces the radial dimension of the automotive suspension actuator, and at the same time, the ultra-low rotational inertia enables the system to have an extremely high dynamic response frequency, which can broaden the operating bandwidth of the automotive suspension to high-frequency continuous bumpy roads.

[0087] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A self-unlocking and energy recovery suspension control method, applied to an automotive suspension, the automotive suspension comprising a lead screw, a motor rotor, and a motor stator, wherein the lead screw and the motor rotor are threadedly connected, characterized in that, The method includes: The axial force change rate of the lead screw, the angular velocity of the motor rotor, and the back electromotive force of the motor stator are obtained. The self-locking index is calculated based on the axial force change rate, the angular velocity, and the back electromotive force. When the self-locking index is greater than the preset self-locking threshold, the motor rotor and the lead screw are driven to rotate relative to each other based on the preset micro-motion torque pulse, and it is determined whether the axial lock between the lead screw and the motor rotor is released. When the axial lock between the lead screw and the motor rotor is released, the preset micro-torque pulse is disconnected, and the motor rotor and the motor stator are controlled to enter the energy recovery mode.

2. The method according to claim 1, characterized in that, The calculation of the self-locking index based on the axial force change rate, the angular velocity, and the back electromotive force includes: An exponential term is constructed within a preset sliding time window based on the angular velocity and the back electromotive force. The axial force change rate is weighted based on the exponential term to obtain the weighted axial force change rate. The self-locking index is obtained by integrating the weighted rate of change of axial force within the preset sliding time window. Specifically, when the motor rotor angular velocity and the back electromotive force approach zero, the exponential term approaches one; when the motor rotor angular velocity and the back electromotive force are not zero, the exponential term approaches zero.

3. The method according to claim 2, characterized in that, The construction of the exponential term within a preset sliding time window based on the angular velocity and the back electromotive force includes: The sum of the squares of the angular velocity and the back electromotive force is obtained by taking the squares of each. The exponent value is obtained by multiplying the sum of squares by a preset weighting coefficient and taking the negative value. The exponent term is obtained based on the exponent value and the base of the natural logarithm.

4. The method according to claim 1, characterized in that, The rate of change of axial force on the lead screw is obtained by differentiating the axial force on the lead screw. The step of driving the motor rotor to rotate relative to the lead screw based on a preset micro-torque pulse, and determining whether the axial lock between the lead screw and the motor rotor is released, includes: Before triggering the preset micro-torque pulse, determine the peak value of the axial force on the lead screw; After triggering the preset micro-torque pulse, the current axial force on the lead screw is determined, and the force drop ratio is calculated based on the current axial force and the peak value of the axial force. If the force drop ratio is greater than a preset drop ratio threshold, it is determined that the axial lock between the lead screw and the motor rotor has been released.

5. The method according to claim 1, characterized in that, The step of driving the motor rotor and the lead screw to rotate relative to each other based on a preset micro-torque pulse, and determining whether the axial lock between the lead screw and the motor rotor is released, includes: During the relative rotation of the motor rotor and the lead screw driven by the preset micro-motion torque pulse, the phase current change rate of the motor stator is determined; When the phase current change rate changes from a positive value to a negative value, it is determined that the axial lock between the lead screw and the motor rotor has been released; The change of the phase current change rate from positive to negative indicates that the motor rotor rotates under the drive of the preset micro-torque pulse, thereby increasing the back electromotive force. The increase in back electromotive force indicates that the axial lock between the lead screw and the motor rotor has been released.

6. The method according to claim 1, characterized in that, The control of the motor rotor and the motor stator to enter the energy recovery mode includes: Disconnect the drive power output to the motor stator and recover the electrical energy generated by the rotation of the motor rotor under the drive of the lead screw.

7. A self-unlocking and energy recovery suspension control system, applied to an automotive suspension, the automotive suspension comprising a lead screw, a motor rotor, and a motor stator, wherein the lead screw and the motor rotor are threadedly connected, characterized in that, The system includes: The acquisition module is used to acquire the axial force change rate of the lead screw, the angular velocity of the motor rotor, and the back electromotive force of the motor stator; The processing module is used to calculate the self-locking index based on the axial force change rate, the angular velocity and the back electromotive force; when the self-locking index is greater than the preset self-locking threshold, the motor rotor and the lead screw are driven to rotate relative to each other based on the preset micro-motion torque pulse, and it is determined whether the axial lock between the lead screw and the motor rotor is released. The energy recovery module is used to disconnect the preset micro-torque pulse when the axial lock between the lead screw and the motor rotor is released, thereby controlling the motor rotor and the motor stator to enter the energy recovery mode.

8. The self-unlocking and energy recovery suspension control system according to claim 7, characterized in that, The processing module is used to: construct an exponential term within a preset sliding time window based on the motor rotor angular velocity and the back electromotive force; weight the rate of change of the axial force on the lead screw based on the exponential term to obtain the weighted rate of change of the axial force on the lead screw; integrate the weighted rate of change of the axial force on the lead screw within the preset sliding time window to obtain the self-locking exponent; wherein, when the motor rotor angular velocity and the back electromotive force tend to zero, the exponential term tends to one; when the motor rotor angular velocity and the back electromotive force are not zero, the exponential term tends to zero.

9. A car suspension, characterized in that, The vehicle suspension also includes a lead screw, a motor rotor, a motor stator, and a controller; the lead screw is threadedly connected to the motor rotor, and the controller is used to implement the self-unlocking and energy recovery suspension control method according to any one of claims 1-6.

10. The automobile suspension according to claim 9, characterized in that, The motor rotor is cylindrical, and the inner wall of the motor rotor has threads. The lead screw passes through the motor rotor and is threadedly connected to the motor rotor through the threads.

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