Automatic damping strength adjusting method and system for new energy vehicle shock absorber

Abstract

The application discloses a new energy automobile shock absorber damping strength automatic adjusting method and system, and relates to the damping adjusting field.The front feed estimation mechanism of the energy recovery torque signal is introduced, the disturbance trend is predicted in combination with the torque change rate, the front and rear suspension dampings are actively adjusted by using the front feed control law, and the pre-compensation is formed before the actual occurrence of the pitching disturbance.Meanwhile, by fusing the front feed and the feedback control, the residual disturbance is further eliminated on the basis of suppressing the initial impact.In addition, the fusion strategy of the system space energy function modeling and the characteristic space dynamic reconstruction optimizes the cooperative action of the front feed, the feedback and the reference damping, avoids the control signal conflict, and takes into account the response speed and the control precision.The scheme fully utilizes the torque foresight information of the energy recovery system and the vehicle body posture feedback data, realizes the rapid suppression of the pitching disturbance, and improves the driving comfort.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of damping adjustment, and more particularly, to a new energy vehicle shock absorber damping strength automatic adjustment method and system. BACKGROUND

[0002] With the popularization of new energy vehicles, energy recovery technology has become a key to improving endurance and energy efficiency. However, when strong braking recovery occurs, the forward braking torque generated by the wheels and the ground is transmitted to the vehicle body, which can cause the vehicle to pitch or drag, resulting in a pitching motion. Especially in frequent start-stop or complex working conditions, this instantaneous and significant pitching disturbance can significantly reduce the driving comfort and become one of the main reasons for poor user experience. Therefore, effectively suppressing or slowing down the pitching disturbance during energy recovery and improving driving comfort are important challenges in the current vehicle suspension control field.

[0003] In order to improve the driving comfort and handling stability of the vehicle, various adaptive or active suspension systems have been widely used in the prior art to adjust the damping characteristics of the shock absorber to adapt to different road conditions and driving states. These systems usually rely on collecting signals such as vehicle body acceleration, wheel bounce, and even some vehicle dynamic parameters, and through feedback control, the damping force of the shock absorber is adjusted in real time according to the actual vehicle motion state. However, for the pitching disturbance caused by the energy recovery process specific to new energy vehicles, pure feedback control often has a certain lag. The system needs to first perceive that the vehicle body has already undergone a pitching motion (such as a change in pitch angular velocity or longitudinal acceleration), and then calculates and applies the corresponding damping adjustment. This makes it difficult to effectively suppress the initial pitching impact in a timely manner when energy recovery begins or changes suddenly, and passengers may still feel a significant nodding sensation. At the same time, traditional suspension control strategies usually do not fully utilize the forward-looking torque information provided by the energy recovery system of new energy vehicles to predict and respond to impending pitching disturbances. This limits the response speed and optimization level of the system to this specific dynamic disturbance.

[0004] Therefore, the existing method still has the defects of insufficient response speed and incomplete suppression when dealing with the pitching disturbance caused by new energy vehicle energy recovery, making it difficult to fully meet the higher demands of users for comfort. SUMMARY

[0005] In order to solve the above technical problems, the present application is proposed.

[0006] According to an aspect of the present application, a new energy vehicle shock absorber damping strength automatic adjustment method is provided, which comprises:

[0007] obtaining a real-time energy recovery torque signal and a vehicle body posture sensor signal;

[0008] signal analyzing the real-time energy recovery torque signal to obtain an effective energy recovery torque;

[0009] pitch disturbance feedforward estimation on the effective energy recovery torque to obtain an estimated feedforward pitch moment and a pitch disturbance tendency index;

[0010] damping compensation feedforward calculation based on the estimated feedforward pitch moment and the pitch disturbance tendency index to obtain a feedforward damping adjustment vector;

[0011] signal analyzing the vehicle body attitude sensor signal to obtain a filtered longitudinal acceleration and a filtered pitch angular velocity, and attitude feedback and damping correction on the filtered longitudinal acceleration and the filtered pitch angular velocity to obtain a feedback damping adjustment vector;

[0012] fusing the feedforward damping adjustment vector, the feedback damping adjustment vector and a reference damping vector to obtain a shock absorber control signal.

[0013] According to another aspect of the present application, a new energy vehicle shock absorber damping strength automatic adjustment system is provided, which comprises:

[0014] a signal acquisition module for acquiring a real-time energy recovery torque signal and a vehicle body attitude sensor signal;

[0015] an energy recovery torque analysis module for signal analyzing the real-time energy recovery torque signal to obtain an effective energy recovery torque;

[0016] a pitch disturbance feedforward estimation module for pitch disturbance feedforward estimation on the effective energy recovery torque to obtain an estimated feedforward pitch moment and a pitch disturbance tendency index;

[0017] a feedforward damping adjustment module for damping compensation feedforward calculation based on the estimated feedforward pitch moment and the pitch disturbance tendency index to obtain a feedforward damping adjustment vector;

[0018] a feedback damping adjustment module for signal analyzing the vehicle body attitude sensor signal to obtain a filtered longitudinal acceleration and a filtered pitch angular velocity, and attitude feedback and damping correction on the filtered longitudinal acceleration and the filtered pitch angular velocity to obtain a feedback damping adjustment vector;

[0019] a shock absorber control signal generation module for fusing the feedforward damping adjustment vector, the feedback damping adjustment vector and a reference damping vector to obtain a shock absorber control signal.

[0020] Compared with the prior art, the new energy vehicle shock absorber damping strength automatic adjustment method and system provided by the application introduces a feedforward estimation mechanism of energy recovery torque signal, calculates the equivalent longitudinal force generated by energy recovery in advance and the target pitch moment, combines the torque change rate to predict the disturbance trend, actively adjusts the front and rear suspension damping (such as differentially adjusting the compression / tension damping according to the feedforward pitch moment direction), forms a pre-compensation before the pitch disturbance actually occurs, and significantly shortens the system response delay. At the same time, by fusing feedforward and feedback control (based on the filtered longitudinal acceleration to dynamically adjust the PID integral gain, and with the pitch angular velocity error to drive closed-loop correction), the residual disturbance is further eliminated on the basis of suppressing the initial impact, and the attitude stability is ensured. In addition, the fusion strategy of system space energy function modeling and characteristic space dynamic reconstruction optimizes the synergistic effect of feedforward, feedback and reference damping, avoids control signal conflict, and balances response speed and control accuracy. The scheme fully utilizes the torque foresight information of the energy recovery system and the vehicle body attitude feedback data, realizes the rapid suppression of the pitch disturbance, and improves the driving comfort. BRIEF DESCRIPTION OF DRAWINGS

[0021] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description of embodiments of the present application, when taken in conjunction with the accompanying drawings. The drawings provided in the specification and the embodiments of the present application together serve to explain the present application and, therefore, to provide further understanding of the present application, and form a part of the specification. The drawings do not limit the present application, but serve to explain the present application together with the embodiments of the present application. In the drawings, the same reference numerals generally represent the same components or steps.

[0022] Figure 1 A flowchart of the new energy vehicle shock absorber damping strength automatic adjustment method according to the embodiments of the present application.

[0023] Figure 2 A flowchart of step S3 in the new energy vehicle shock absorber damping strength automatic adjustment method according to the embodiments of the present application.

[0024] Figure 3 A flowchart of step S5 in the new energy vehicle shock absorber damping strength automatic adjustment method according to the embodiments of the present application.

[0025] Figure 4 A block diagram of the new energy vehicle shock absorber damping strength automatic adjustment system according to the embodiments of the present application. DETAILED DESCRIPTION

[0026] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0027] In view of the problems in the background art mentioned above, the present application proposes an automatic adjustment method for the damping strength of shock absorbers in new energy vehicles. Figure 1 This is a flowchart of an automatic adjustment method for the damping strength of a shock absorber in a new energy vehicle according to an embodiment of this application. Figure 1 As shown, the automatic adjustment method for damping strength of a shock absorber in a new energy vehicle according to an embodiment of this application includes: S1, acquiring a real-time energy recovery torque signal and a vehicle attitude sensor signal; S2, performing signal analysis on the real-time energy recovery torque signal to obtain an effective energy recovery torque; S3, performing pitch disturbance feedforward estimation on the effective energy recovery torque to obtain an estimated feedforward pitch moment and a pitch disturbance trend index; S4, performing damping compensation feedforward calculation based on the estimated feedforward pitch moment and the pitch disturbance trend index to obtain a feedforward damping adjustment vector; S5, performing signal analysis on the vehicle attitude sensor signal to obtain a filtered longitudinal acceleration and a filtered pitch angular velocity, and performing attitude feedback and damping correction on the filtered longitudinal acceleration and the filtered pitch angular velocity to obtain a feedback damping adjustment vector; S6, fusing the feedforward damping adjustment vector, the feedback damping adjustment vector, and the reference damping vector to obtain a shock absorber control signal.

[0028] In step S1, real-time energy recovery torque signal and vehicle body attitude sensor signal are acquired. It should be understood that the purpose of acquiring the real-time energy recovery torque signal is to capture the original excitation source information causing the vehicle pitch disturbance, i.e. the braking torque generated by energy recovery. This signal is directly output or controlled by the vehicle power system, and has better foresight and predictability compared to the vehicle body attitude change, which can provide a basis for the feedforward control path, so as to predict the trend and intensity of the pitch motion before it has fully developed or occurs, and realize faster and more active intervention. At the same time, the purpose of acquiring the real-time vehicle body attitude sensor signal (for example, containing longitudinal acceleration and pitch angular velocity information) is to monitor the current actual motion state of the vehicle, especially the dynamic response related to pitch. This signal provides a basis for the feedback control path, so that the system can correct the damping setting according to the actual vehicle body motion deviation, compensate for disturbances that cannot be completely suppressed by feedforward control, or respond to attitude changes caused by other unknown disturbances, so as to ensure the stability and comfort of the vehicle attitude. By simultaneously acquiring and comprehensively utilizing the feedforward information of the energy recovery torque and the feedback information of the vehicle body attitude, the present method can construct a control strategy combining the advantages of feedforward and feedback, aiming to more effectively and timely suppress the pitch disturbance in the energy recovery process and overcome the lagging defect of the existing pure feedback control.

[0029] Specifically, step S1 can be implemented in the following way: the real-time energy recovery torque signal is derived from the power control unit (PCU) or motor controller of the new energy vehicle, which is responsible for managing the operating mode of the motor, including the torque output during energy recovery. As a real-time state parameter, this torque signal is periodically broadcast or subscribed by the shock absorber controller through the high-speed communication network inside the vehicle, such as the controller area network (CAN) bus. The control unit responsible for executing the shock absorber damping adjustment (such as the suspension controller or integrated chassis controller) listens to or reads the data frame corresponding to the energy recovery torque signal identifier on the CAN bus through its built-in CAN communication interface hardware and corresponding communication protocol software. After receiving the data frame, the software layer parses the original data, extracts the current real-time energy recovery torque value, and performs necessary unit conversion or calibration to obtain the effective energy recovery torque that can be directly used for subsequent calculation. The cycle frequency of acquiring this signal needs to be high enough to capture the rapid changes of torque, for example, it can be set to tens of hertz to hundreds of hertz, to ensure the real-time requirements of the control system.

[0030] The acquisition of the vehicle body attitude sensor signals relies on the attitude sensor unit installed on the vehicle, such as an inertial measurement unit (IMU), which integrates sensors such as accelerometers and gyroscopes inside. These sensors measure the acceleration and angular velocity of the vehicle in various directions in real time, including the longitudinal acceleration and the pitch angular velocity around the lateral axis of the vehicle. The IMU unit will preliminarily process the measured raw data and send the processed attitude information to the shock absorber control unit in real time through the vehicle's CAN bus or other suitable communication interface. The shock absorber control unit also receives and analyzes the data frames from the attitude sensor through its communication interface, extracting the current real-time longitudinal acceleration value and pitch angular velocity value. These sensor signals are also transmitted and collected at a high frequency, such as the energy recovery torque signal acquisition frequency or higher, to accurately reflect the dynamic response of the vehicle body.

[0031] In step S2, the real-time energy recovery torque signal is analyzed to obtain the effective energy recovery torque. Accordingly, considering that the raw real-time energy recovery torque signal obtained from the vehicle communication network or sensor may contain noise, interference, or its value does not directly correspond to the braking force generated by the drive wheels on the ground that can cause the vehicle body to pitch. There may be internal system losses, nonlinear control strategies, and sensor errors during the actual generation and transmission of the energy recovery torque. Therefore, the raw signal needs to be processed as necessary to accurately extract the effective energy recovery torque component that actually acts on the wheels and converts into ground longitudinal force, which in turn causes the vehicle body to pitch, ensuring that the subsequent feedforward pitch disturbance estimation based on this torque is more accurate and reliable, thereby providing high-quality input data for precise feedforward damping compensation of the shock absorber and improving the performance of the entire control system and the suppression effect on pitch disturbance.

[0032] Specifically, step S2 can be implemented as follows: the real-time energy recovery torque signal is generated by the vehicle's power control module (PCU) or motor controller and broadcasted through the vehicle's internal CAN communication network. The shock absorber control unit (or integrated controller responsible for this function) receives CAN messages containing energy recovery torque information through its CAN communication hardware interface. These messages are packaged in the format of the predetermined vehicle communication protocol, with specific data fields storing the original energy recovery torque data, which may be represented as integers, floating-point numbers or other formats. The first step of signal analysis is to identify and read these specific CAN messages and extract the field containing the original torque data. For example, according to the vehicle's CAN communication matrix specification, the energy recovery torque information is stored in the data segment (such as bytes 4-5) of a specific CAN ID (such as 0x123). The controller software will read the corresponding byte data according to these specifications.

[0033] The extracted raw data is a quantized or scaled digital value, which needs to be converted into an engineering unit with physical meaning, i.e. Newton meter (Nm). This conversion process relies on the calibration data of the vehicle, including the scale factor and offset between the raw data and the actual physical torque. For example, the calibration data shows that the raw data is a 16-bit unsigned integer, representing a scaled torque value, and the unit conversion relationship is: Effective energy recovery torque (Nm) = (raw data value * Scale) + Offset. Scale and Offset are constants determined in advance during vehicle development and calibration, and are stored in the non-volatile memory of the control unit. For example, Scale is set to 0.1 Nm / count, and Offset is set to 0 Nm. If the raw torque data value extracted from the CAN message is 3000, the effective energy recovery torque obtained after analysis and conversion is (3000 * 0.1 Nm / count) + 0 Nm = 300 Nm. In addition, the analysis process also includes filtering the extracted data, such as using a low-pass filter to filter out communication noise or sensor high-frequency vibration caused by burr, to ensure that the output effective energy recovery torque signal is smooth and stable, and more truly reflects the actual power system output, thereby improving the accuracy of subsequent feedforward estimation. This series of data reading, format analysis, unit conversion and filtering process constitutes the complete implementation process of converting the raw real-time energy recovery torque signal into the effective energy recovery torque used for control calculation.

[0034] In step S3, the effective energy recovery torque is subjected to pitch disturbance feedforward estimation to obtain an estimated feedforward pitch moment and a pitch disturbance trend indicator. It should be understood that the energy recovery torque is a direct external excitation source causing the pitch motion of the new energy vehicle. By monitoring and estimating this excitation source in real time, the size of the pitch moment that the excitation source will produce and its change speed (trend) can be predicted before the vehicle body actually changes significantly in pitch attitude. This cause-based forward-looking estimation enables the control system to know the characteristics of the upcoming disturbance in advance. Compared with feedback control relying on vehicle body attitude sensor signals (whose response occurs after the disturbance has caused attitude changes), feedforward estimation uses the prediction ability of the disturbance source signal to calculate the required damping adjustment earlier, thereby exerting a restraining effect at the beginning or early stage of pitch motion, significantly reducing the response lag of the control system, improving the suppression effect of the energy recovery caused transient pitch impact, and thus greatly improving the ride comfort.

[0035] Figure 2 The flowchart for step S3 in the method for automatically adjusting the damping strength of the shock absorber of the new energy vehicle according to the embodiment of the present application. Specifically, in the embodiment of the present application, as shown in FIG. 3, the pitch disturbance trend indicator is calculated by the following formula: Pitch disturbance trend indicator = (pitch disturbance feedforward torque - pitch disturbance feedback torque) / pitch disturbance feedback torque. The pitch disturbance feedback torque is the torque value obtained by the pitch disturbance feedback control of the vehicle body attitude sensor signal, and the pitch disturbance feedforward torque is the torque value obtained by the pitch disturbance feedforward control of the energy recovery torque signal. The pitch disturbance trend indicator is a dimensionless quantity, which represents the change speed of the pitch disturbance. The larger the value, the faster the change speed of the pitch disturbance. The pitch disturbance trend indicator is used as an input parameter of the pitch disturbance feedforward control, which is used to calculate the required damping adjustment amount of the shock absorber. Figure 2As shown, in step S3, the effective energy recovery torque is fed forward to estimate the estimated feed-forward pitch moment and the pitch disturbance tendency indicator, including: S31, based on the effective energy recovery torque and the tire radius, calculating the equivalent longitudinal force generated by energy recovery; S32, based on the equivalent longitudinal force and the height of the center of gravity, calculating the target pitch moment generated by the equivalent longitudinal force as the estimated feed-forward pitch moment; S33, calculating the rate of change of the effective energy recovery torque as the pitch disturbance tendency indicator.

[0036] It should be understood that the energy recovery torque is a rotational effect acting on the wheel shaft, and the longitudinal force (braking force) generated by the interaction between the wheel and the ground is the direct cause of the pitch motion of the vehicle body. It is this longitudinal force acting on the ground contact point of the wheel, and relative to the center of gravity of the vehicle, which forms a force arm, thereby forming a pitch moment that causes the vehicle to nod or lift the tail. Therefore, the conversion of the energy recovery torque into the equivalent longitudinal force is a key physical quantity conversion process connecting the output of the power system and the dynamic response of the vehicle attitude.

[0037] Specifically, step S31 can be implemented by the following method: first, the real-time effective energy recovery torque obtained in the previous step is obtained. The torque represents the actual braking torque generated by the current energy recovery system on the drive axle. At the same time, the tire radius of the vehicle needs to be obtained. The tire radius is a fixed parameter of the vehicle, which refers to the effective working radius of the vehicle tire, such as the wheel radius under static load or the dynamic radius considering the speed influence. In order to simplify and ensure real-time, a preset nominal tire radius value is used here, which can be determined according to the tire specifications and models of the vehicle, actual measurement or reference to vehicle design parameters. For example, for common passenger cars, the tire radius can be set to about 0.3 meters. The process of calculating the equivalent longitudinal force is based on the basic principle of mechanics: the torque acting on a rotating object is equal to the tangential force multiplied by the action radius. Therefore, by dividing the effective energy recovery torque by the tire radius, the equivalent longitudinal force generated by the energy recovery at the contact point of the wheel and the ground can be obtained. The size of this longitudinal force is the direct excitation force that causes the vehicle to pitch. For example, if the measured effective energy recovery torque is 300 Nm and the preset tire radius is 0.3 m, the equivalent longitudinal force generated by energy recovery is 300 Nm / 0.3 m = 1000 N. This calculation process is carried out in real time in the software of the shock absorber control unit to ensure that the latest equivalent longitudinal force value is obtained, providing real-time input for subsequent pitch moment estimation.

[0038] Accordingly, although the equivalent longitudinal force is the direct cause of the vehicle pitch, the physical quantity actually causing the vehicle body to rotate around its lateral axis (i.e., the pitch motion) is the moment. The longitudinal force acts on the contact point between the wheel and the ground, while the pitch motion of the vehicle occurs around the center of gravity of the vehicle. Therefore, it is necessary to calculate the moment of the longitudinal force acting on the ground relative to the center of gravity of the vehicle. The height of the center of gravity of the vehicle is a key parameter for determining this moment, as it represents the vertical distance from the action line of the longitudinal force (along the ground) to the horizontal line of the center of gravity of the vehicle, i.e., the effective force arm forming the pitch moment. Through this calculation, the effect of the ground longitudinal force can be converted into a moment input in the direction of the vehicle pitch, which directly represents the disturbance strength and direction of the energy recovery to the vehicle pitch posture, thereby providing a prediction value directly reflecting the disturbance size for the subsequent feedforward control, so that the controller can make targeted damping compensation.

[0039] Specifically, step S32 can be implemented in the following way: first, the equivalent longitudinal force generated by energy recovery calculated in real time in the previous step is obtained. At the same time, the height of the center of gravity of the vehicle needs to be obtained. The height of the center of gravity of the vehicle is an inherent parameter representing the mass distribution of the vehicle, which is determined by theoretical calculation or actual measurement during the design stage of the vehicle. In the suspension control system, the height of the center of gravity is stored in the memory of the control unit as a preset constant parameter. For example, for a certain type of new energy vehicle, the height of the center of gravity can be set to 0.6 meters. Based on the physical principle that the moment is equal to the force multiplied by the force arm, the equivalent longitudinal force obtained in the previous step is multiplied by the height of the center of gravity, i.e., the pitch moment generated by the longitudinal force is calculated. Specifically, if the equivalent longitudinal force is F and the height of the center of gravity is h, the estimated feedforward pitch moment M = F*h. For example, if the calculated equivalent longitudinal force is 1000 Newton and the height of the center of gravity of the vehicle is set to 0.6 meters, the estimated feedforward pitch moment calculated is 1000 Newton*0.6 meters = 600 Newton meters. This calculation process is executed in real time in the processor of the shock absorber control unit, using the latest equivalent longitudinal force value and the stored height of the center of gravity parameter, to quickly and accurately calculate the estimated pitch moment at the current time or about to occur. The target pitch degree (i.e., the estimated feedforward pitch moment) calculated is then used for damping compensation feedforward calculation to guide the system how to adjust the shock absorber damping in advance to resist this predicted pitch disturbance.

[0040] It should be appreciated that knowing only the current equivalent longitudinal force (or the estimated feedforward pitch moment), although providing information of the magnitude of the disturbance, is not enough to fully characterize the dynamic nature of the disturbance and its potential impact on the vehicle attitude. The rate of change of the energy recovery torque, i.e. its rate of change, reflects the abruptness or gentleness of the energy recovery process. For example, a rapidly increasing energy recovery torque will cause a more severe and abrupt pitch jerk than a torque of the same final magnitude but increasing slowly. Therefore, taking the rate of change of the torque as an independent indicator, additional forward-looking information about the pitch disturbance trend and dynamic strength can be provided. This trend indicator enables the control system to not only predict the magnitude of the pitch moment to be generated, but also to predict whether this moment is emerging sharply or accumulating slowly, thereby guiding the feedforward control to make more refined and timely damping adjustments according to the dynamic characteristics of the disturbance, especially when dealing with sudden energy recovery braking, helping to more effectively suppress the initial nodding impact and further improve the ride comfort.

[0041] Specifically, step S33 can be implemented by the following way: real-time calculating the rate of change of the effective energy recovery torque requires tracking the change of this torque over time. This is achieved by numerically differentiating the continuously collected samples of the effective energy recovery torque. Inside the shock absorber control unit, a register or buffer is maintained to store the value of the effective energy recovery torque of the last or several times. When the system acquires the current real-time effective energy recovery torque value T_current at each control period (for example, the period is Delta_T, between a few milliseconds to tens of milliseconds, depending on the system processing power and control requirements, for example, set to 10 milliseconds), the effective energy recovery torque value T_previous acquired in the previous control period can be used to calculate its rate of change. The formula for calculating the rate of change can be approximated as the difference between the current torque value and the previous torque value divided by the time interval between the two sampling times (i.e. the control period). Specifically, the rate of change of the energy recovery torque = (T_current - T_previous) / Delta_T. For example, if the effective energy recovery torque value acquired in the previous control period is 250 Nm, the value acquired in the current control period is 300 Nm, and the control period is 10 milliseconds (i.e. 0.01 seconds), the calculated energy recovery torque rate of change is (300 Nm - 250 Nm) / 0.01 seconds = 50 Nm / 0.01 seconds = 5000 Nm / second. In order to improve robustness, especially in the presence of signal noise, a linear fitting slope within a sliding window or a low-pass filter can also be used to smooth the difference result, but the core idea is to quantify the change amplitude of the torque in unit time. This change rate value calculated is used as the said pitch disturbance trend indicator, together with the estimated feedforward pitch moment calculated before, as input into the lookup table based on the control law, to jointly determine the size and direction of the feedforward damping adjustment vector. After the calculation is completed, the current T_current value will be stored as the T_previous value for the next control period.

[0042] In step S4, a feedforward damping compensation calculation is performed based on the estimated feedforward pitch moment and the pitch disturbance tendency indicator to obtain a feedforward damping adjustment vector. Accordingly, the previous step has estimated the magnitude of the pitch moment caused by energy recovery and the tendency of the disturbance to develop. This step is to utilize these predictions to calculate the pre-compensation damping adjustment that needs to be applied to the dampers, i.e. the feedforward damping adjustment vector, according to a pre-set control strategy or model. This vector represents how the system should proactively adjust the damper damping to counter the predicted pitch disturbance before the actual sensing of the vehicle body attitude change. Through this calculation, the system is able to generate a part of the control signal in advance so that the dampers can react at the very beginning of the pitch motion or its rapid development, thus achieving a fast and proactive disturbance suppression, making up for the response delay of pure feedback control and significantly improving the ride comfort during energy recovery.

[0043] Specifically, in the embodiment of the present application, the damping compensation feedforward calculation based on the estimated feedforward pitch moment and the pitch disturbance tendency indicator to obtain a feedforward damping adjustment vector comprises: obtaining a current vehicle speed; inputting the current vehicle speed, the estimated feedforward pitch moment and the pitch disturbance tendency indicator into a look-up table based on a control law to obtain the feedforward damping adjustment vector.

[0044] It can be understood that the driving speed of the vehicle is a key operating parameter affecting the dynamic characteristics of the vehicle and the working state of the suspension system. The response characteristics of the vehicle to external excitations (including the pitch moment generated by energy recovery) will change with the vehicle speed. For example, at high speed, the pitch inertia effect, tire longitudinal force characteristics and aerodynamic effect of the vehicle are significantly different from those at low speed or stationary state. Therefore, in order to enable the feedforward control strategy to provide the most suitable and effective damping compensation for the current actual working condition, the vehicle speed needs to be taken as an important input variable for determining the feedforward damping adjustment vector.

[0045] In particular, the current vehicle speed can be obtained by means of the sensors already available on the vehicle. The most common way is to use the wheel speed sensors of the vehicle. These sensors (electromagnetic or Hall sensors installed near each wheel) measure the rotational speed or angular position of the wheels in real time and send these signals to the vehicle's anti-lock braking system (ABS), electronic stability control system (ESC) or vehicle controller. The shock absorber control unit obtains these wheel speed sensor data through the vehicle's internal communication network, such as the CAN bus. To obtain the overall speed of the vehicle, the control unit processes the signals from multiple wheels, calculates the linear speed of each wheel by multiplying the wheel speed by a pre-set or estimated effective rolling radius of the tire, and then combines multiple wheel speed signals (for example, takes the average of the wheel speeds without significant slip) to calculate the reference speed of the vehicle. For example, if the angular speed of a wheel is 100 radians per second and the effective rolling radius of the tire is set to 0.3 meters (this radius value can be determined during vehicle calibration and stored), the linear speed of the wheel is 100*0.3=30 meters per second, which is equivalent to 108 kilometers per hour. By performing similar calculations and averaging multiple wheel speeds, the real-time vehicle speed can be obtained. In particular, the frequency of obtaining the wheel speed signal is consistent with or higher than the sampling frequency of the control system to ensure that the vehicle speed information used for feedforward calculation is real-time and accurate.

[0046] Accordingly, the previous step has prospectively estimated the size of the pitch disturbance caused by energy recovery (estimated feedforward pitch moment) and its dynamic characteristics (pitch disturbance trend indicator), while obtaining the key parameter of vehicle speed reflecting the current operating state of the vehicle. In order to effectively suppress this predicted disturbance, it is necessary to determine the precise feedforward damping adjustment amount that the shock absorber should apply based on this information. Therefore, the present application inputs the current vehicle speed, the estimated feedforward pitch moment and the pitch disturbance trend indicator into a control law-based lookup table to obtain the feedforward damping adjustment vector. Inputting these inputs into a control law-based lookup table is an effective method of mapping multi-dimensional inputs to optimal or predetermined outputs (i.e. feedforward damping adjustment vector). It is worth mentioning that the lookup table internally stores optimal shock absorber feedforward damping adjustment strategies corresponding to different operating conditions (combined by vehicle speed, disturbance size and trend) determined by offline optimization or experience. Through fast lookup table or interpolation, the system can obtain the specific damping adjustment instructions required for the current predicted disturbance and vehicle state in real time and efficiently, avoid complex real-time model calculations, ensure the rapid response capability of the control system, and thus achieve precise and timely feedforward suppression of the pitch disturbance caused by energy recovery.

[0047] More specifically, in the embodiments of the present application, inputting the current vehicle speed, the estimated feedforward pitch moment and the pitch disturbance tendency indicator into a control law based lookup table to obtain the feedforward damping adjustment vector comprises: increasing the compression damping of the front suspension and increasing the extension damping of the rear suspension when the estimated feedforward pitch moment is greater than zero; increasing the extension damping of the front suspension and increasing the compression damping of the rear suspension when the estimated feedforward pitch moment is less than zero.

[0048] It should be appreciated that the estimated feedforward pitch moment greater than zero represents that the energy recovery braking is causing or will cause the vehicle to have a nodding pitch motion. When the vehicle is nodding, the front of the vehicle moves downward, causing the front suspension to be compressed; meanwhile, the rear of the vehicle moves upward, causing the rear suspension to be extended. In order to effectively suppress this specific pitch tendency, damping forces need to be applied to the suspensions to counteract these motions. Increasing the compression damping of the front suspension can resist the compression velocity of the front suspension when the front of the vehicle is sinking, thereby slowing down the downward movement of the front; increasing the extension damping of the rear suspension can resist the extension velocity of the rear suspension when the rear of the vehicle is lifting, thereby suppressing the upward movement of the rear. By simultaneously and purposefully increasing the damping forces of the front and rear suspensions in the directions corresponding to their motion directions (front compression, rear extension), a moment opposite to the pitch motion tendency can be generated, thereby actively damping or canceling the pitch vibration caused by energy recovery, improving the stability and comfort of the vehicle during braking.

[0049] Likewise, the estimated feedforward pitch moment less than zero represents that the vehicle is experiencing or will experience a pitch motion tendency of lifting the head or sitting back. Although nodding is more common in energy recovery braking, there can be negative pitch moments in certain transitional operating conditions or specific vehicle designs. When the vehicle is lifting the head or sitting back, the front of the vehicle moves upward, causing the front suspension to be extended; meanwhile, the rear of the vehicle moves downward, causing the rear suspension to be compressed. In order to effectively suppress this motion, damping forces need to be purposefully increased to resist these motion directions. Increasing the extension damping of the front suspension can resist the extension velocity of the front suspension when the front of the vehicle is lifting, thereby slowing down the upward movement of the front; increasing the compression damping of the rear suspension can resist the compression velocity of the rear suspension when the rear of the vehicle is sinking, thereby suppressing the downward movement of the rear. By simultaneously and purposefully increasing the damping forces of the front and rear suspensions in the directions corresponding to their motion directions (front extension, rear compression), a moment opposite to the pitch motion tendency can be generated, thereby actively damping or canceling the potential negative pitch vibration, improving the stability and comfort of the vehicle in these operating conditions.

[0050] In particular, the two steps of increasing the compression damping of the front suspension and increasing the extension damping of the rear suspension when the estimated feedforward pitch moment is greater than zero and increasing the extension damping of the front suspension and increasing the compression damping of the rear suspension when the estimated feedforward pitch moment is less than zero are specific rules or mechanisms for calculating or determining the feedforward damping adjustment vector.

[0051] Specifically, inputting the current vehicle speed, the estimated feedforward pitch moment and the pitch disturbance tendency indicator into the control law based lookup table to obtain the feedforward damping adjustment vector can be achieved by the following way: firstly, real-time input data needs to be obtained: current vehicle speed value (obtained through vehicle bus, for example from vehicle speed sensor signal), estimated feedforward pitch moment value (obtained through calculation of previous step, including sign), and pitch disturbance tendency indicator value (obtained through calculation of previous step). These input values are the basis of implementing feedforward control, which provides information about the current motion state of the vehicle and the characteristics of the upcoming pitch disturbance (direction, magnitude, tendency).

[0052] A multi-dimensional lookup table is pre-stored in the electronic control unit. This lookup table is created and optimized during the vehicle design and development and control system calibration phase. It is an offline calculation result set based on control law, which associates a variety of input parameter combinations (vehicle speed, estimated feedforward pitch moment, pitch disturbance tendency indicator) with the corresponding optimal feedforward damping adjustment (i.e. feedforward damping adjustment vector). For example, when a working condition appears in simulation or test with vehicle speed of 70 km / h, estimated feedforward pitch moment of +700 Nm (corresponding to acceleration head-up), and pitch disturbance tendency indicator of high, according to the control law, the compression damping of the front suspension and the stretch damping of the rear suspension should be increased at this time. After optimization calculation, it is determined that the compression damping of the front suspension (left / right) needs to be increased by +180 Ns / m, the stretch damping of the rear suspension (left / right) needs to be increased by +150 Ns / m, and the adjustment amount of the stretch damping of the front suspension and the compression damping of the rear suspension is 0 or a small value. This set of values (for example, +180, 0, +180, 0, 0, +150, 0, +150) is taken as the feedforward damping adjustment vector, which is stored in the lookup table corresponding to the input combination (vehicle speed = 70 km / h, estimated moment = +700 Nm, tendency indicator = high). The content of this lookup table directly reflects the required control strategy, including determining the main damping adjustment direction according to the positive and negative of the estimated feedforward pitch moment. For example, during the calibration phase, when the simulated or tested vehicle is in a working condition representing a positive estimated feedforward pitch moment (such as acceleration head-up), the engineer will calculate and determine that the compression damping of the front suspension and the stretch damping of the rear suspension should be increased at this time according to the desired control effect, and store these increase amounts as the corresponding component values of the feedforward damping adjustment vector in the lookup table corresponding to the input of this working condition. Similarly, when a working condition representing a negative estimated feedforward pitch moment (such as energy recovery nodding) is encountered, the position corresponding to this working condition in the lookup table will store the adjustment amounts of increasing the stretch damping of the front suspension and the compression damping of the rear suspension as vector components. The size of these adjustment amounts depends not only on the direction of the moment, but also on the magnitude of the moment, the current vehicle speed and the pitch disturbance tendency indicator, and these relationships are pre-embedded in the data of the lookup table.

[0053] During actual vehicle operation, the shock absorber control unit uses the real-time acquired current vehicle speed, the estimated feedforward pitch moment and the pitch disturbance tendency index values as multi-dimensional indices to query this pre-set lookup table in each control cycle. Since the real-time input values are unlikely to exactly match all the discrete calibration points in the lookup table, the system will perform a multi-dimensional interpolation algorithm (for example, a three-dimensional lookup table usually adopts tri-linear interpolation). The interpolation process calculates a smooth transition output value according to the relative positions of the real-time input values between their nearest lookup table data points and the stored data of these points. For example, if the real-time vehicle speed is 55 km / h, the estimated moment is -450 Nm, and the tendency index is 0.7, the system will find the discrete points closest to these values and calculate the corresponding output according to the interpolation algorithm. The result of the interpolation calculation is a vector containing multiple components, where each component value represents the damping adjustment amount (for example, in units of Newton seconds per meter) that the feedforward control part recommends to apply to a specific shock absorber (for example, front left, front right, rear left, rear right) in a specific working mode (compression or stretching) under the current predicted working condition. This vector obtained through lookup table query and interpolation is the feedforward damping adjustment vector, which contains specific damping adjustment instructions required for feedforward compensation of the predicted pitch disturbance, for example, it may contain front left stretching damping adjustment amount +110 Ns / m, rear right compression damping adjustment amount +85 Ns / m, and other components may be 0 or small values.

[0054] In step S5, the vehicle body attitude sensor signals are signal-analyzed to obtain a filtered longitudinal acceleration and a filtered pitch angular velocity, and the filtered longitudinal acceleration and the filtered pitch angular velocity are subjected to attitude feedback and damping correction to obtain a feedback damping adjustment vector. It should be understood that although the feedforward control is introduced to cope with the predictive disturbance caused by energy recovery, the feedback control is still an important part to ensure the stability of the vehicle attitude. The vehicle body attitude sensors (such as accelerometers and gyroscopes) can measure the actual motion state of the vehicle in real time, including longitudinal acceleration and pitch angular velocity. These signals directly reflect whether and how much the current pitch motion of the vehicle occurs. Therefore, through analysis and filtering processing, accurate and smooth attitude information can be extracted from the original sensor data. Based on these actually measured attitude information, the feedback control algorithm can calculate the damping correction amount required to suppress the current occurred pitch motion. This feedback mechanism can respond to various unknown disturbances or residual disturbances that the feedforward control fails to completely eliminate, forming a closed-loop control loop to continuously adjust the shock absorber damping, ensuring that the vehicle can maintain the desired attitude stability under various working conditions, and improving the overall driving comfort and handling.

[0055] Specifically, the signal analysis of the vehicle body attitude sensor signal to obtain the filtered longitudinal acceleration and the filtered pitch angular velocity can be realized in the following way: first, the vehicle body attitude sensor signal is converted into digital signal by the sensor module or the dedicated control unit through analog-to-digital conversion (ADC). These digital signals are then transmitted to the control unit responsible for the shock absorber control through the vehicle internal communication network (such as CAN bus). After the control unit receives these digitized sensor signals, the signal analysis process is carried out. This involves converting the original digital values into physically meaningful units, such as converting the output of the acceleration sensor into longitudinal acceleration represented by meters per second squared (m / s²) and converting the output of the gyroscope into pitch angular velocity represented by radians per second (rad / s). This conversion requires the use of parameters such as scale factor and offset determined by the sensor during the calibration stage. For example, the digital output value of a certain accelerometer is multiplied by a preset sensitivity coefficient (such as 0.01 m / s² / bit) and added to a preset zero point offset (such as 0.05 m / s²), thereby obtaining the current longitudinal acceleration raw value.

[0056] Next, the raw longitudinal acceleration and pitch angular velocity signals obtained by analysis are filtered. Sensor signals often have high-frequency noise or vibration interference, and direct use will cause the control system to malfunction or performance to decline. Therefore, a digital filter (such as a low-pass filter) is applied to attenuate or remove these unwanted high-frequency components, thereby obtaining a smooth and accurate signal reflecting the actual trend of the vehicle body. The specific type (such as Butterworth filter, Kalman filter, etc.) and parameters (such as cutoff frequency) of the filter need to be determined in advance according to the characteristics of the vehicle and the characteristics of the noise during the system development and calibration stage and stored in the control unit. For example, a second-order low-pass filter with a cutoff frequency set to 10 Hz can be applied to filter the analyzed longitudinal acceleration signal to obtain the filtered longitudinal acceleration; at the same time, the analyzed pitch angular velocity signal is filtered to obtain the filtered pitch angular velocity. The final output is the filtered longitudinal acceleration and the filtered pitch angular velocity signals after analysis and filtering, which are used for subsequent attitude feedback control.

[0057] Figure 3 The flow chart for step S5 in the new energy vehicle shock absorber damping strength automatic adjustment method according to the embodiments of the present application. Specifically, in the embodiments of the present application, as shown in FIG. 5, the control unit responsible for the shock absorber control receives the filtered longitudinal acceleration and the filtered pitch angular velocity signals from the sensor module or the dedicated control unit through the vehicle internal communication network (such as CAN bus). After receiving these signals, the control unit carries out the following steps to determine the current vehicle body attitude and the corresponding damping strength adjustment value. Figure 3As shown, in step S5, the vehicle body attitude sensor signal is signal-analyzed to obtain a filtered longitudinal acceleration and a filtered pitch angular velocity, and the filtered longitudinal acceleration and the filtered pitch angular velocity are subjected to attitude feedback and damping correction to obtain a feedback damping adjustment vector, including: S51, adjusting an integral gain in a PID controller based on the filtered longitudinal acceleration to obtain a fine-tuning PID controller; S52, calculating an error between the filtered pitch angular velocity and a target pitch angular velocity; S53, inputting the error into the fine-tuning PID controller to obtain the feedback damping adjustment vector.

[0058] Correspondingly, the standard PID controller may not achieve optimal performance in all operating conditions when processing a system with time-varying dynamic characteristics. In particular, the integral term, although it can eliminate steady-state error, in the process of severe pitch transient caused by large vehicle acceleration or deceleration, excessive integral gain may cause the control system to respond slowly, have severe overshoot and even oscillate, and reduce ride comfort. By dynamically adjusting the integral gain of the PID controller according to the real-time longitudinal acceleration, the system can make the controller more adaptive to the current longitudinal motion state, appropriately reduce the integral action to enhance transient response and stability when there is large acceleration or deceleration, and increase the integral action to ensure accurate tracking of pitch angular velocity error and elimination of steady-state error when there is smooth or small acceleration or deceleration.

[0059] Specifically, step S51 can be implemented in the following way: first, receive the filtered longitudinal acceleration value (for example, in meters per second squared). This value is a real-time scalar input that represents the current longitudinal acceleration or deceleration of the vehicle. The control unit internally stores a pre-determined integral gain mapping relationship based on the control law, which is determined during vehicle development and calibration. This mapping relationship exists in the form of a lookup table, which stores the corresponding PID integral gain values (or an adjustment coefficient relative to the basic integral gain) at different longitudinal acceleration discrete points. This lookup table is obtained through a large number of vehicle dynamics simulations and actual road tests, and its purpose is to determine the integral gain that can achieve the best pitch control effect of the vehicle under various acceleration and deceleration conditions.

[0060] In each control cycle, the control unit queries this pre-defined lookup table using the current filtered longitudinal acceleration value as an index. For example, the lookup table defines a discrete data point of using base integral gain value Kibase when longitudinal acceleration is 0 m / s2, using 0.7*Kibase when longitudinal acceleration is +4 m / s2 (acceleration), using 0.6*K_i_base when longitudinal acceleration is -5 m / s2 (deceleration), etc. If the real-time acquired longitudinal acceleration value does not exactly match any of the discrete points in the lookup table (e.g., real-time acceleration is -3.2 m / s2), the control unit performs an interpolation calculation (e.g., linear interpolation) to calculate the corresponding integral gain value according to the relative position of -3.2 m / s2 between -5 m / s2 and 0 m / s2 of the two adjacent calibration points (e.g., the interpolation calculation results in an integral gain of 0.72*K_i_base to be used at this acceleration. This calculated value is the PID controller integral gain adjusted according to the current longitudinal acceleration.

[0061] It can be appreciated that the basic principle of a feedback control system is to compare the actual output state of the system (here, the filtered pitch angular velocity) with the desired target state, and to drive the controller to produce a regulating action through the difference (i.e., the error) to reduce or eliminate this error. In particular, in the present application, the target pitch angular velocity is 0 rad / s, which directly reflects the control objective of the suspension control system in the energy recovery process: to suppress or prevent the dynamic pitch rotation of the vehicle body as much as possible, i.e., to keep the pitch angular velocity of the vehicle body close to zero, so as to maintain the stability of the vehicle, reduce the nodding or lifting impact felt by the passengers, and improve the driving comfort.

[0062] Specifically, step S52 can be implemented by the following method: the method of calculating the error is to perform a subtraction operation, subtracting the filtered actual pitch angular velocity from the target pitch angular velocity. That is, error = 0 - filtered actual pitch angular velocity, which means that the error is equal to the negative value of the filtered actual pitch angular velocity. For example, if the filtered actual pitch angular velocity measurement value is positive 0.1 rad / s (indicating that the vehicle head is lifted upward), the calculated error is 0 - 0.1 = -0.1 rad / s. If the filtered actual pitch angular velocity is negative 0.05 rad / s (indicating that the vehicle head is diving downward), the calculated error is 0 - (-0.05) = 0.05 rad / s.

[0063] Accordingly, the core of the feedback control is to generate control commands based on the deviation between the current actual motion state and the desired state of the vehicle. The pitch angular velocity error calculated in real time is input into the PID controller, so that the controller can use the proportional, integral and derivative information of the error to comprehensively evaluate the deviation, duration and trend of the current pitch motion. Based on this information, the PID controller can calculate the required feedback control output, which is then converted into a damping adjustment command for the shock absorber.

[0064] Specifically, step S53 can be implemented by inputting the filtered pitch angular velocity error value (e.g., in rad / s) calculated in the previous step into the PID control algorithm module implemented in the control unit. This PID controller is a fine-tuned PID controller with an integral gain (Ki) adjusted in the previous step, and its proportional gain (Kp), integral gain (Ki, determined dynamically according to longitudinal acceleration) and derivative gain (Kd) are set in advance through simulation or experimental calibration. The controller calculates three control components in real time based on the input error value: a proportional term (proportional to the current error), an integral term (proportional to the accumulated value of the error over time, with a gain of dynamically adjusted Ki), and a derivative term (proportional to the rate of change of the error). For example, if the current error is E, the integral error accumulation value is ∫Edt, and the error change rate is dE / dt, the original output of the PID controller can be conceptually represented in the form of Kp*E+Ki*(longitudinal acceleration)*∫Edt+Kd*dE / dt (note that Ki(longitudinal acceleration) here indicates that the integral gain is a function of longitudinal acceleration). After these components are weighted and summed, a feedback control signal is formed. This feedback control signal is then mapped or converted into a feedback damping adjustment vector. This vector contains specific damping adjustment amounts for each adjustable shock absorber of the vehicle (e.g., front left, front right, rear left, rear right) and its different motion directions (compression, stretching). The mapping relationship is pre-set, for example, the sign and size of the PID output determine how much the compression / stretching damping of the front / rear suspension needs to be increased or decreased. For example, a positive PID output indicates that the front suspension compression damping and the rear suspension stretching damping need to be increased, and the amount of increase is related to the size of the PID output. The final output of this feedback damping adjustment vector represents the correction amount that the feedback control part suggests for each shock absorber damping to correct the current pitch angular velocity error, for example, front left compression damping adjustment +50 Ns / m, rear right stretching damping adjustment +30 Ns / m, etc.

[0065] In step S6, the feedforward damping adjustment vector, the feedback damping adjustment vector and the reference damping vector are fused to obtain a shock absorber control signal. Accordingly, the reference damping vector represents a preset basic damping characteristic of the vehicle in a normal driving state, for maintaining basic driving stability and comfort. The feedforward damping adjustment vector predicts and offsets potential pitch disturbance in advance using energy recovery information, and has the advantage of fast response. The feedback damping adjustment vector is corrected in real time according to the actual attitude error of the vehicle, compensates for insufficient feedforward or deals with unanticipated disturbance, and provides robustness. By fusing the three, the respective advantages can be comprehensively utilized to generate a comprehensive shock absorber control signal, so that the suspension system can quickly respond to the pitch impact caused by energy recovery and continuously stabilize the vehicle attitude, thereby maximizing the driving comfort and stability of the new energy vehicle in the energy recovery working condition, and overcoming the hysteresis problem of the pure feedback control in the prior art.

[0066] Specifically, in the embodiment of the present application, fusing the feedforward damping adjustment vector, the feedback damping adjustment vector and the reference damping vector to obtain a shock absorber control signal comprises: adding the feedforward damping adjustment vector, the feedback damping adjustment vector and the reference damping vector to obtain a target damping instruction; and performing amplitude limiting processing on the target damping instruction and then performing signal conversion to obtain the shock absorber control signal.

[0067] Specifically, the feedforward damping adjustment vector, the feedback damping adjustment vector and the reference damping vector are added to obtain a target damping instruction. It can be understood that adding the three is a direct method of constructing a comprehensive control strategy. In this way, it can be ensured that the final target damping of the shock absorber simultaneously reflects the basic performance requirement, the advance response to the predicted disturbance and the timely correction of the actual error, thereby forming a more perfect, robust and rapid response control instruction, and maximizing the driving comfort and stability of the new energy vehicle in the energy recovery process.

[0068] In particular, the summing of the feedforward damping adjustment vector, the feedback damping adjustment vector and the reference damping vector to obtain the target damping command can be achieved by vector addition of the feedforward damping adjustment vector, the feedback damping adjustment vector and the reference damping vector. Each vector contains values corresponding to different control modes of each adjustable shock absorber of the vehicle (e.g. front left compression damping, front left rebound damping, front right compression damping, and so on until rear right rebound damping). The control unit performs the summing by position (or called "component") of these three vectors. For example, the first component of the final target damping command vector (representing the target value of front left compression damping) is equal to the first component of the reference damping vector plus the first component of the feedforward damping adjustment vector plus the first component of the feedback damping adjustment vector. This process is performed in parallel or sequentially for all components to obtain the target damping command vector as the target damping command.

[0069] Preferably, in another example, the summing of the feedforward damping adjustment vector, the feedback damping adjustment vector and the reference damping vector to obtain the target damping command can be achieved by the following way: it can be understood that, instead of directly adding the reference damping amount with the feedforward damping adjustment amount and the feedback damping adjustment amount, by summing the feedforward damping adjustment vector, the feedback damping adjustment vector and the reference damping vector, the damping feedforward adjustment feature and the damping feedback adjustment feature in the real-time energy recovery torque signal and the vehicle body posture sensor signal can be more effectively related, thereby improving the control accuracy of the shock absorber control signal.

[0070] Based on this, in the embodiments of the present application, the summing of the feedforward damping adjustment vector, the feedback damping adjustment vector and the reference damping vector to obtain the target damping command comprises: correlating the feedforward damping adjustment vector and the feedback damping adjustment vector by a system space energy function to obtain a correlation reference state representation vector; taking the correlation reference state representation vector as an adaptive gain state, and performing homomorphic projection mapping with the feedforward damping adjustment vector and the feedback damping adjustment vector respectively to obtain a feedforward damping mapping adjustment vector and a feedback damping mapping adjustment vector; taking the reference damping vector as a chain state prior, and performing feature space dynamic reconstruction on the feedforward damping mapping adjustment vector and the feedback damping mapping adjustment vector to obtain a modified feedforward damping adjustment vector and a modified feedback damping adjustment vector; and summing the modified feedforward damping adjustment vector, the modified feedback damping adjustment vector and the reference damping vector by position to obtain a target damping command vector as the target damping command.

[0071] That is, considering the energy characteristic representation of the feedforward damping adjustment vector corresponding to the real-time energy recovery torque signal and the spatial characteristic representation of the feedback damping adjustment vector corresponding to the vehicle attitude sensor signal, the correlation model of the feedforward damping adjustment vector and the feedback damping adjustment vector is first performed using the system spatial energy function as follows: ;in, For transpose operation, It is vector multiplication. It is the feedforward damping adjustment vector. It is the feedback damping adjustment vector, and and All are row vectors. It is the correlation baseline state representation vector. That is, using the energy characteristics of different states (i.e., kinetic-potential energy states) as the conjugate momentum of energy-space correlation, the functional self-equilibrium correlation of different energy states under energy-space is carried out.

[0072] Then, the above-mentioned correlation benchmark state representation vector As the adaptive gain state, it is homomorphically projected onto both the feedforward damping adjustment vector and the feedback damping adjustment vector: ;in, It is a dot product by position. It is the feedforward damping mapping adjustment vector. It is the feedback damping mapping adjustment vector;

[0073] The reference damping vector is then expressed, for example, as... As a chain of state priors, the feature space is dynamically reconstructed as follows: ;in, It is subtracted based on position. It is the reference damping vector. It is a calculation The reciprocal of each eigenvalue, It is the corrected feedforward damping adjustment vector. It is a correction feedback damping adjustment vector;

[0074] Thus, the corrected feedforward damping adjustment vector is then... The feedback damping adjustment vector and the reference damping vector By performing positional summation, the feature space can be dynamically reconstructed (association-preserving reconstruction) while maintaining its respective associated state and the reference associated state through spatial adaptive isomorphic projection under different characteristic energy states. This achieves correlation-preserving summation of the feedforward damping adjustment vector, the feedback damping adjustment vector, and the reference damping vector, thereby improving the control accuracy of the shock absorber control signal.

[0075] Specifically, the target damping command is subjected to amplitude limiting and then signal conversion to obtain the shock absorber control signal. Accordingly, the damping coefficient or damping force of the shock absorber has physical minimum and maximum limits. Directly sending the target damping command obtained by summation to the actuator will not only fail to achieve the desired damping effect, but also may cause control failure, and even damage the shock absorber or affect the stability of the vehicle in severe cases. Amplitude limiting ensures that the output command value always falls within the effective range that the shock absorber can achieve. Subsequent signal conversion is necessary because the target damping command output by the control algorithm is in physical units (such as Newton seconds per meter or Newton), while the actuator of the shock absorber, such as a solenoid valve or motor, needs to receive a specific form of electrical signal (such as current, voltage, or pulse width modulation PWM signal) to adjust the damping. This conversion converts the theoretical target damping value into an actual control signal that the actuator can understand and execute, thereby achieving precise adjustment of the damping of the shock absorber.

[0076] Specifically, the target damping command is subjected to amplitude limiting and then signal conversion to obtain the shock absorber control signal can be achieved in the following way: first, the target damping command (target damping command vector) obtained by summation in the previous step, which contains multiple components, is subjected to amplitude limiting. Each component of this vector represents the target damping value that each shock absorber of the vehicle is expected to achieve in the compression or extension direction. For each component in the vector, the system compares it with the minimum damping limit and the maximum damping limit of the working mode corresponding to the shock absorber. These limits are determined according to the physical characteristics of the shock absorber itself (such as valve structure, motor capacity, etc.) and the results of vehicle dynamics calibration (upper and lower bounds set to ensure comfort, handling, and safety), and are stored in the control unit. If the value of a certain component is less than its corresponding minimum limit, it is set to the minimum value; if it is greater than the maximum limit, it is set to the maximum value; if it is between the minimum and maximum limits, it remains unchanged. For example, the compression mode damping range of a certain shock absorber is 100 Ns / m to 800 Ns / m. If the target compression damping command obtained by summation is 50 Ns / m, it will be limited to 100 Ns / m after amplitude limiting; if it is 900 Ns / m, it will be limited to 800 Ns / m; if it is 450 Ns / m, it will remain 450 Ns / m.

[0077] The result of the clipping process is a clipped target damping command vector, whose values are still physical quantities representing damping. Next, signal conversion is performed. The control unit converts the clipped target damping values into corresponding electrical signals according to the type and characteristics of the shock absorber actuators. This is achieved through a lookup table or a mathematical model. The lookup table or model describes the nonlinear correspondence between shock absorber damping values and control signals (such as current), which has been determined during the shock absorber factory or vehicle calibration stage. For example, the lookup table specifies that a target damping value of 100 Ns / m corresponds to a 0.1 ampere current, a target damping value of 450 Ns / m corresponds to a 0.4 ampere current, and a target damping value of 800 Ns / m corresponds to a 0.7 ampere current. The control unit looks up or calculates the electrical signal value corresponding to the clipped target damping value (linear interpolation is required). The final output is a shock absorber control signal vector, where each component is a specific electrical signal value (for example, in amperes or as a percentage representing the PWM duty cycle) used to drive the corresponding shock absorber actuator. These signals are then sent to each shock absorber through the drive circuit, achieving precise damping adjustment.

[0078] In summary, the new energy vehicle shock absorber damping strength automatic adjustment method based on the embodiments of the present application is illustrated. By introducing a feedforward estimation mechanism of energy recovery torque signal, the equivalent longitudinal force generated by energy recovery is calculated in advance, and the disturbance trend is predicted by combining the torque rate, the front and rear suspension damping is actively adjusted using the feedforward control law (such as differentially adjusting compression / tension damping according to the direction difference of the feedforward pitch moment), and pre-compensation is formed before the pitch disturbance actually occurs, significantly shortening the system response delay. At the same time, by fusing feedforward and feedback control (based on filtered longitudinal acceleration to dynamically adjust PID integral gain, and pitch angular velocity error to drive closed-loop correction), residual disturbance is further eliminated on the basis of suppressing initial impact, ensuring posture stability. In addition, the fusion strategy of system space energy function modeling and characteristic space dynamic reconstruction optimizes the synergistic effect of feedforward, feedback, and reference damping, avoids control signal conflicts, and balances response speed and control accuracy. This scheme fully utilizes the torque lookahead information of the energy recovery system and the vehicle body posture feedback data to achieve rapid suppression of pitch disturbance and improve ride comfort.

[0079] Figure 4 The block diagram of the new energy vehicle shock absorber damping strength automatic adjustment system according to the embodiments of the present application is shown in FIG. 1. As shown in FIG. 1, the system includes a control unit 100, a torque sensor 200, a pitch sensor 300, a longitudinal acceleration sensor 400, and a plurality of shock absorber actuators 500. Figure 4As shown, the new energy vehicle shock absorber damping strength automatic adjustment system 100 according to the embodiment of the application comprises: a signal acquisition module 110, configured to acquire a real-time energy recovery torque signal and a vehicle body posture sensor signal; an energy recovery torque analysis module 120, configured to perform signal analysis on the real-time energy recovery torque signal to obtain an effective energy recovery torque; a pitch disturbance feedforward estimation module 130, configured to perform pitch disturbance feedforward estimation on the effective energy recovery torque to obtain an estimated feedforward pitch moment and a pitch disturbance trend index; a feedforward damping adjustment module 140, configured to perform damping compensation feedforward calculation based on the estimated feedforward pitch moment and the pitch disturbance trend index to obtain a feedforward damping adjustment vector; a feedback damping adjustment module 150, configured to perform signal analysis on the vehicle body posture sensor signal to obtain a filtered longitudinal acceleration and a filtered pitch angular velocity, and to perform posture feedback and damping correction on the filtered longitudinal acceleration and the filtered pitch angular velocity to obtain a feedback damping adjustment vector; and a shock absorber control signal generation module 160, configured to fuse the feedforward damping adjustment vector, the feedback damping adjustment vector and a reference damping vector to obtain a shock absorber control signal.

[0080] Here, those skilled in the art can understand that the specific operations of each step in the above new energy vehicle shock absorber damping strength automatic adjustment system have been described in detail above with reference to the description of the new energy vehicle shock absorber damping strength automatic adjustment method Figures 1 to 3 , and therefore, the repeated description thereof will be omitted.

Claims

1. A method for automatically adjusting the damping strength of a shock absorber in a new energy vehicle, characterized in that, include: Acquire real-time energy recovery torque signals and vehicle attitude sensor signals; The real-time energy recovery torque signal is analyzed to obtain the effective energy recovery torque; The effective energy recovery torque is subjected to pitch disturbance feedforward estimation to obtain the estimated feedforward pitch moment and pitch disturbance trend index; Based on the estimated feedforward pitch moment and the pitch disturbance trend index, damping compensation feedforward calculation is performed to obtain the feedforward damping adjustment vector. The vehicle attitude sensor signal is analyzed to obtain the filtered longitudinal acceleration and the filtered pitch velocity, and attitude feedback and damping correction are performed on the filtered longitudinal acceleration and the filtered pitch velocity to obtain the feedback damping adjustment vector. The feedforward damping adjustment vector, the feedback damping adjustment vector, and the reference damping vector are fused to obtain the damper control signal.

2. The automatic adjustment method for damping strength of shock absorbers in new energy vehicles according to claim 1, characterized in that, The effective energy recovery torque is subjected to pitch disturbance feedforward estimation to obtain the estimated feedforward pitch moment and pitch disturbance trend index, including: Based on the effective energy recovery torque and tire radius, calculate the equivalent longitudinal force generated by energy recovery; Based on the equivalent longitudinal force and center of gravity height, the target pitch force generated by the equivalent longitudinal force is calculated as the estimated feedforward pitch moment; The rate of change of the effective energy recovery torque is calculated as the pitch disturbance trend index.

3. The automatic adjustment method for damping strength of shock absorbers in new energy vehicles according to claim 2, characterized in that, Based on the estimated feedforward pitch moment and the pitch disturbance trend index, damping compensation feedforward calculation is performed to obtain the feedforward damping adjustment vector, including: Get the current vehicle speed; The current vehicle speed, the estimated feedforward pitch moment, and the pitch disturbance trend index are input into a lookup table based on the control law to obtain the feedforward damping adjustment vector.

4. The automatic adjustment method for damping strength of shock absorbers in new energy vehicles according to claim 3, characterized in that, The current vehicle speed, the estimated feedforward pitch moment, and the pitch disturbance trend index are input into a lookup table based on the control law to obtain the feedforward damping adjustment vector, including: When the estimated feedforward pitch moment is greater than zero, increase the compression damping of the front suspension and the tension damping of the rear suspension. When the estimated feedforward pitch moment is less than zero, increase the tension damping of the front suspension and the compression damping of the rear suspension.

5. The automatic adjustment method for damping strength of shock absorbers in new energy vehicles according to claim 1, characterized in that, The vehicle attitude sensor signal is analyzed to obtain the filtered longitudinal acceleration and filtered pitch velocity. Attitude feedback and damping correction are then applied to the filtered longitudinal acceleration and filtered pitch velocity to obtain a feedback damping adjustment vector, including: The integral gain in the PID controller is adjusted based on the filtered longitudinal acceleration to obtain a fine-tuned PID controller. Calculate the error between the filtered pitch rate and the target pitch rate; The error is input into the fine-tuning PID controller to obtain the feedback damping adjustment vector.

6. The automatic adjustment method for damping strength of shock absorbers in new energy vehicles according to claim 5, characterized in that, The target's pitch angular velocity is 0 rad / s.

7. The automatic adjustment method for damping strength of shock absorbers in new energy vehicles according to claim 1, characterized in that, The damper control signal is obtained by fusing the feedforward damping adjustment vector, the feedback damping adjustment vector, and the reference damping vector, including: The feedforward damping adjustment vector, the feedback damping adjustment vector, and the reference damping vector are summed to obtain the target damping command; The target damping command is subjected to amplitude limiting processing and then signal conversion to obtain the shock absorber control signal.

8. The automatic adjustment method for damping strength of shock absorbers in new energy vehicles according to claim 7, characterized in that, The target damping command is obtained by summing the feedforward damping adjustment vector, the feedback damping adjustment vector, and the reference damping vector, including: Correlation modeling is performed on the feedforward damping adjustment vector and the feedback damping adjustment vector using the system space energy function to obtain the correlation benchmark state representation vector; The correlation reference state representation vector is used as the adaptive gain state, and is homomorphically projected onto the feedforward damping adjustment vector and the feedback damping adjustment vector to obtain the feedforward damping mapping adjustment vector and the feedback damping mapping adjustment vector, respectively. Using the reference damping vector as a chain-like state prior, the feature space is dynamically reconstructed for the feedforward damping mapping adjustment vector and the feedback damping mapping adjustment vector to obtain the modified feedforward damping adjustment vector and the modified feedback damping adjustment vector. The modified feedforward damping adjustment vector, the modified feedback damping adjustment vector, and the reference damping vector are summed by position to obtain the target damping command vector, which is used as the target damping command.

9. An automatic damping strength adjustment system for shock absorbers in new energy vehicles, characterized in that, include: The signal acquisition module is used to acquire real-time energy recovery torque signals and vehicle attitude sensor signals; An energy recovery torque analysis module is used to analyze the real-time energy recovery torque signal to obtain the effective energy recovery torque. The pitch disturbance feedforward estimation module is used to perform pitch disturbance feedforward estimation on the effective energy recovery torque to obtain the estimated feedforward pitch moment and pitch disturbance trend index. The feedforward damping adjustment module is used to perform damping compensation feedforward calculation based on the estimated feedforward pitch moment and the pitch disturbance trend index to obtain the feedforward damping adjustment vector. The feedback damping adjustment module is used to perform signal analysis on the vehicle attitude sensor signal to obtain the filtered longitudinal acceleration and the filtered pitch velocity, and to perform attitude feedback and damping correction on the filtered longitudinal acceleration and the filtered pitch velocity to obtain the feedback damping adjustment vector. The shock absorber control signal generation module is used to fuse the feedforward damping adjustment vector, the feedback damping adjustment vector, and the reference damping vector to obtain the shock absorber control signal.

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