An intelligent collaborative control method and system for automobile shock absorber
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHONGQING GUOGUI RACING TECHNOLOGY CO LTD
- Filing Date
- 2026-06-01
- Publication Date
- 2026-06-30
Smart Images
Figure CN122300142A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of vehicle shock absorber control technology, specifically to an intelligent collaborative control method and system for automotive shock absorbers. Background Technology
[0002] As vehicle requirements for ride comfort, handling stability, and chassis response consistency continue to increase, continuously adjustable damping shock absorbers are increasingly widely used in passenger car suspension systems. These shock absorbers typically adjust the valve opening by regulating the current in the electromagnetic proportional valve coil, thereby achieving continuous adjustment of the damping force. Existing semi-active suspension control methods mostly calculate the target damping force based on signals such as vehicle acceleration, suspension travel, vehicle speed, steering, and braking, and then convert the target damping force into a current command output to the shock absorber actuator.
[0003] However, in actual vehicle operation, time delays are introduced by controller calculations, bus communication, solenoid valve current establishment, and valve core mechanical response. This results in differences between the piston relative speed, stroke direction, and output damping force range at the moment the command takes effect and the current sampling state. If the target damping force is directly calculated based on the current state, it is easy to cause a mismatch between the target force and the actual execution capability of the shock absorber. At the same time, the damping characteristics of the shock absorber are affected by factors such as the rate of change of current, oil temperature, and differences in compression and recovery strokes. Simply using a post-event limiting method to handle the excessive target force may disrupt the damping force distribution relationship between the four wheels, making it difficult to simultaneously control the vertical, pitch, and roll of the vehicle body, and may cause sudden current changes, saturation dwell, and attitude control deviations. Summary of the Invention
[0004] This application provides an intelligent collaborative control method and system for automotive shock absorbers, which at least solves some of the technical problems existing in the related technologies described above.
[0005] According to a first aspect of the embodiments of this application, an intelligent collaborative control method for automotive shock absorbers is provided, comprising: Collect vehicle sensor signals and read the current to estimate the vehicle's vertical speed, pitch speed, roll speed, and the relative speed of the shock absorber pistons; The overall response delay of the shock absorber is determined based on the calculated communication delay and the overall response time of the solenoid valve. Using the overall response delay as a time reference, the corresponding piston relative velocity is extrapolated to the effective time to obtain the predicted value of piston relative velocity, and the stroke direction at the corresponding effective time is determined. Based on the current, current change rate, overall response delay, and current limit, calculate the current range that each damper can achieve at the moment of activation; map each current range, the corresponding predicted piston relative velocity, and the corresponding stroke direction at the moment of activation to the range of achievable damping force. The vehicle modal control target is generated based on the vehicle's vertical velocity, pitch velocity, and roll velocity; the target damping force is solved using the achievable damping force range as a constraint and the vehicle modal control target as a reference input. The coil current command is obtained by reverse lookup based on the predicted values of the target damping force and piston relative velocity, and then output to the corresponding solenoid valve drive circuit.
[0006] As an optional solution, the vehicle sensor signals include vehicle vertical acceleration, longitudinal acceleration, lateral acceleration, yaw rate, steering angle, vehicle speed, suspension travel, wheel speed, braking status signal, and vehicle stability control system request signal; the controller estimates the vehicle vertical speed based on the rate of change of vehicle vertical acceleration and suspension travel, estimates pitch rate and roll rate based on longitudinal acceleration, lateral acceleration, wheelbase, and track width, and obtains the piston relative speed based on the rate of change of suspension travel.
[0007] As an optional approach, determining the overall response delay of the shock absorber includes: reading the overall response time of the solenoid valve from a calibration lookup table; the calibration lookup table is indexed by the current current, the direction of current change, and the estimated oil temperature, and the calculated communication delay is added to the corresponding overall response time of the solenoid valve to obtain the overall response delay of the corresponding shock absorber.
[0008] As an optional approach, obtaining the predicted piston relative speed includes: calculating the rate of change of speed based on the piston relative speed of the current control cycle and the piston relative speed of the previous control cycle; multiplying the rate of change of speed by the corresponding comprehensive response delay to obtain a speed extrapolation; and adding the speed extrapolation to the piston relative speed of the current control cycle to obtain the corresponding predicted piston relative speed.
[0009] As an optional approach, the current current is the coil current currently actually executed by each shock absorber as recorded by the controller; the current reachable range includes an upper current limit and a lower current limit, the upper current limit is determined by the current current, the maximum rate of change of current rise, the comprehensive response delay and the current limit value, and the lower current limit is determined by the current current, the maximum rate of change of current fall and the comprehensive response delay.
[0010] As an optional approach, mapping the achievable current range, the corresponding predicted piston relative velocity, and the corresponding stroke direction at the effective time to the achievable damping force range includes: selecting a calibration mapping table based on the stroke direction at the corresponding effective time; inputting the corresponding upper limit of current and the corresponding predicted piston relative velocity into the calibration mapping table to obtain the upper limit of damping force; inputting the corresponding lower limit of current and the corresponding predicted piston relative velocity into the calibration mapping table to obtain the lower limit of damping force; and forming the corresponding achievable damping force range by the lower limit and upper limit of damping force of the same shock absorber.
[0011] As an optional approach, the solution for the target damping force includes: establishing a linear superposition relationship between the damping force and the vehicle body modal response, and using the target damping force as the control variable to be determined; calculating the modal deviations corresponding to the vertical control target, pitch control target, and roll control target based on the linear superposition relationship; and constructing a quadratic programming objective function using the weighted sum of squares of the modal deviation, the change in tire normal load, and the change in coil current.
[0012] As an optional approach, the constraints for solving the target damping force include: each target damping force is within the corresponding achievable damping force range; the product of each target damping force and the corresponding predicted piston relative velocity is not less than zero; the change in current of each coil does not exceed the maximum change within one control cycle; and when the braking state signal or the vehicle stability control system request signal is triggered, a safe lower limit for the damping force of the shock absorber corresponding to the request signal is set.
[0013] As an optional approach, the reverse lookup to obtain the coil current command includes: interpolating the initial coil current command in the corresponding calibration mapping table based on each target damping force, the corresponding predicted value of the piston relative velocity, and the stroke direction at the corresponding effective time; applying a first-order low-pass filter to the initial coil current command to obtain the coil current command, and outputting the coil current command to the corresponding solenoid valve drive circuit.
[0014] According to a second aspect of the embodiments of this application, an intelligent collaborative control system for automotive shock absorbers is also provided, comprising: The signal acquisition and state estimation module is used to acquire vehicle sensor signals and read the current, and estimate the vehicle's vertical speed, pitch speed, roll speed and the relative speed of the shock absorber pistons; The comprehensive response delay determination module is used to determine the comprehensive response delay of the shock absorber based on the calculated communication delay and the comprehensive response time of the solenoid valve. The piston speed prediction module is used to extrapolate the corresponding piston relative speed to the effective time based on each comprehensive response delay, obtain the piston relative speed prediction value, and determine the stroke direction at the corresponding effective time. The module for determining the damping force range is used to calculate the current achievable range of each shock absorber at the moment of activation based on the current, current change rate, comprehensive response delay, and current limit; and to map each current achievable range, the corresponding predicted value of the piston relative velocity, and the corresponding stroke direction at the moment of activation into the achievable damping force range. The target damping force solution module is used to generate the vehicle modal control target based on the vehicle's vertical velocity, pitch angular velocity, and roll angular velocity; and to solve for the target damping force by using the achievable damping force range as a constraint and the vehicle modal control target as a reference input. The current command output module is used to obtain the coil current command based on the predicted values of the target damping force and piston relative speed, and output it to the corresponding solenoid valve drive circuit.
[0015] According to a third aspect of the embodiments of this application, an electronic device is provided, including: a processor; a memory for storing a computer program executable by the processor; wherein the processor is configured to execute the computer program in the memory to implement the method described in the first aspect.
[0016] According to a fourth aspect of the embodiments of this application, a computer-readable storage medium is provided, which, when an executable computer program in the storage medium is executed by a processor, enables the implementation of the method described in the first aspect.
[0017] This application integrates the controller's communication delay calculation, the solenoid valve's overall response time, the current change capability, and the piston's relative speed prediction into the damping force solution process. At the moment the command actually takes effect, the achievable damping force range of each shock absorber is determined, and this range is used as a constraint condition for the overall vehicle damping distribution. Therefore, the target damping force no longer relies on post-event limit correction, reducing the deviation between the target force and the actual executed force, and preventing the coordination relationship of the four corner damping forces from being disrupted due to insufficient capacity of a single shock absorber. By using the vehicle's vertical, pitch, and roll mode control targets as a reference for constraint optimization, the system can rationally distribute the control quantity to shock absorbers with adjustment margins under complex operating conditions, while simultaneously satisfying dissipation, current change rate, and safety lower limit requirements. This improves the attitude control stability of the semi-active suspension under cornering braking, seam impacts, and continuous undulating road surfaces, reduces current surges and saturation dwell phenomena, and improves vehicle ride comfort and handling stability.
[0018] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Furthermore, no embodiment in this disclosure is required to achieve all the effects described above. Attached Figure Description
[0019] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.
[0020] Figure 1 A flowchart of an intelligent collaborative control method for automotive shock absorbers provided in this embodiment of the disclosure.
[0021] Figure 2 A flowchart illustrating the mapping of damping force ranges provided in embodiments of this disclosure.
[0022] Figure 3 A flowchart for solving the target damping force provided in the embodiments of this disclosure.
[0023] Figure 4 A flowchart illustrating the reverse lookup and output of current commands provided in this embodiment of the disclosure.
[0024] Figure 5 This is a schematic block diagram of an intelligent collaborative control system for automotive shock absorbers provided in an embodiment of this disclosure.
[0025] Figure 6 This is a schematic block diagram of an electronic device provided in an embodiment of the present disclosure. Detailed Implementation
[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.
[0027] This disclosure provides an intelligent collaborative control method for automotive shock absorbers, applicable to vehicles with one continuously adjustable damping shock absorber (CDC) on each of the four wheels. Each CDC shock absorber has a built-in electromagnetic proportional valve, and the controller continuously adjusts the damping force by changing the valve opening through adjusting the coil current. The vehicle is equipped with a vertical acceleration sensor, a longitudinal acceleration sensor, a lateral acceleration sensor, a yaw rate sensor, a steering angle sensor, a vehicle speed sensor, four suspension travel sensors, four wheel speed sensors, and interfaces for braking status signals and vehicle stability control system request signals. The chassis domain controller collects all sensor signals at a fixed cycle, completes damping distribution calculations in each control cycle, and outputs coil current commands to the four solenoid valve drive circuits.
[0028] The implementation process of the method described in this application will be described in detail below with reference to specific embodiments. It should be noted that this embodiment is only used to explain this application and is not intended to limit the scope of protection of this application. Conventional adjustments or substitutions of each step by those skilled in the art without departing from the concept of this application should be included in the scope of protection of this application.
[0029] Please see Figure 1 , Figure 1 This is a flowchart of an intelligent collaborative control method for automotive shock absorbers according to an embodiment of the present invention, such as... Figure 1 As shown, the method includes steps S1-S6: In step S1, vehicle sensor signals are acquired and the current is read to estimate the vehicle's vertical speed, pitch speed, roll speed, and the relative speed of the shock absorber pistons.
[0030] Specifically, at the beginning of each control cycle, the controller acquires vehicle sensor signals and simultaneously reads the current actual coil current of the four CDC shock absorbers. The acquired vehicle sensor signals include vertical acceleration, longitudinal acceleration, lateral acceleration, yaw rate, steering angle, vehicle speed, four suspension travels, four wheel speeds, braking status signals, and vehicle stability control system request signals. For the oil temperature required for subsequent table lookup, the controller reads an estimated oil temperature value, which is obtained by the controller based on the historical coil current of each CDC shock absorber, vehicle operating time, and a pre-calibrated oil temperature recursive model. Optionally, if chassis or shock absorber temperature signals are already available, these existing temperature signals can also be used as input for the oil temperature estimate.
[0031] For example, the oil temperature recursive model can be expressed as follows: the controller acquires the coil current of the four CDC shock absorbers from the previous cycle to the current cycle in the kth control cycle, and uses the oil temperature estimate of the previous cycle as the initial value for recursion, and calculates the oil temperature change in the current cycle according to the current heat generation and heat dissipation. Specifically, it can be expressed by the formula: T(k)=T(k-1)+Δt·[Kh·P(k)-Kc(v)·(T(k-1)-Ta)].
[0032] Wherein, T(k) is the estimated oil temperature for the current cycle, T(k-1) is the estimated oil temperature for the previous cycle, Δt is the control cycle or the time interval between two adjacent recursions, Ta is the ambient temperature or the initial temperature when the vehicle is powered on, Kh is the heating correction coefficient, Kc(v) is the heat dissipation correction coefficient related to vehicle speed, and P(k) is the current heating characterization value. P(k) can be determined by the weighted sum of the squares of the currents of the four CDC shock absorber coils. For example, P(k) = a1·I1² + a2·I2² + a3·I3² + a4·I4², where I1 to I4 are the current coil currents of the four CDC shock absorbers, and a1 to a4 are the heating weight coefficients of the corresponding shock absorbers. The vehicle running time is reflected in the recursion process through the continuous accumulation of Δt; the longer the vehicle running time, the more recursions the model performs, and the oil temperature estimate is gradually updated according to the current heating and heat dissipation status. When the vehicle is stationary or traveling at low speed, Kc(v) takes a smaller value; as the vehicle speed increases, Kc(v) increases to reflect the improved heat dissipation capacity due to enhanced airflow. The controller applies upper and lower limit constraints to the recursively obtained oil temperature estimate and uses it as input to the solenoid valve's integrated response time calibration lookup table.
[0033] Based on the above signals, the controller estimates the vehicle's motion state and the relative piston velocities of each CDC shock absorber. Specifically, the controller estimates the vehicle's vertical velocity based on the vehicle's vertical acceleration and the rate of change of the four suspension travels; it estimates the pitch and roll angular velocities based on the longitudinal acceleration, lateral acceleration, and known geometric parameters such as the vehicle's wheelbase and track width; and it obtains the relative piston velocities of each of the four CDC shock absorbers based on the rate of change of the four suspension travels. This velocity characterizes the relative speed of motion between the sprung and unsprung masses. The above estimations can be performed using a linear state observer, which will not be elaborated here.
[0034] In some embodiments, the controller also compensates for the lateral acceleration based on vehicle speed, steering angle, and yaw rate to obtain the compensated lateral acceleration. The purpose of this is to distinguish between the quasi-static lateral force generated by steady-state turning and the transient lateral force caused by road excitation. The compensated lateral acceleration replaces the original lateral acceleration in subsequent roll rate estimation and vehicle modal control target generation, so that roll control can more accurately reflect the impact of dynamic road excitation on the vehicle body.
[0035] The output of the state estimation includes the vehicle's vertical velocity, pitch velocity, roll velocity, and the relative piston velocities of the four CDC shock absorbers.
[0036] In step S2, the overall response delay of the shock absorber is determined based on the calculated communication delay and the overall response time of the solenoid valve.
[0037] After the controller issues the coil current command, the CDC shock absorber needs a certain delay before it actually generates the corresponding damping force change. Specifically, this delay consists of two parts: the calculation communication delay and the solenoid valve comprehensive response time. The calculation communication delay reflects the time consumed by the controller's calculation and bus communication. Under the same control platform, the same value is taken for all four shock absorbers, and it can be calibrated to a fixed value according to the controller hardware specifications during system initialization. The solenoid valve comprehensive response time covers the coil current change process and the valve core mechanical movement process. The controller reads this value from a pre-calibrated lookup table, which is indexed by the current current, the direction of current change, and the estimated oil temperature. In one embodiment, the direction of current change is determined by the actual current change direction available to the corresponding CDC damper at the start of the current control cycle. Specifically, the controller compares the current current read in the current control cycle with the actual execution coil current read in the previous control cycle; if the current current is higher than the actual execution coil current of the previous control cycle and the difference exceeds a preset current threshold, it is determined to be the current rising direction; if the current current is lower than the actual execution coil current of the previous control cycle and the difference exceeds a preset current threshold, it is determined to be the current falling direction; when the absolute value of the difference does not exceed the preset current threshold, the controller looks up tables for both the current rising and falling directions, and uses the larger of the solenoid valve's overall response time to calculate the overall response delay. When the current rises from a low value, the coil inductance effect causes a longer response time; when the current falls from a high value, the response time is shorter. Increased oil viscosity at low temperatures also slows down valve core movement and increases the overall response time.
[0038] The calculated communication delay is added to the corresponding solenoid valve's overall response time to obtain the overall response delay of the corresponding CDC shock absorber. Taking a CDC shock absorber as an example, let the current time be... Its overall response delay is The effective time when the damping force actually changes is This delay is updated once per control cycle, and all subsequent calculations related to the shock absorber's performance are based on this delay. Using time as a reference, the overall response delay is typically in the range of several milliseconds to tens of milliseconds, with the specific value depending on the solenoid valve model and the controller hardware platform.
[0039] In step S3, using the comprehensive response delay as the time reference, the corresponding piston relative velocity is extrapolated to the effective time to obtain the piston relative velocity prediction value, and the stroke direction at the corresponding effective time is determined.
[0040] Since the control command takes effect only after a comprehensive response delay, the piston relative velocity at the moment of activation has deviated from the current sampled value. Therefore, it needs to be extrapolated to the moment of activation. Specifically, the rate of change of velocity is calculated based on the piston relative velocity of the current control cycle and the piston relative velocity of the previous control cycle; this rate of change of velocity is then compared with the corresponding comprehensive response delay. Multiply to obtain the speed extrapolation; add the speed extrapolation to the piston relative speed of the current control cycle to obtain the corresponding piston relative speed prediction value. This method is a first-order linear extrapolation, which can achieve sufficient accuracy with low computational load in most operating conditions. Optionally, when the vehicle is under high-frequency road excitation conditions, a second-order extrapolation can be used to improve the prediction accuracy.
[0041] After extrapolation is completed, the controller determines the stroke direction at the corresponding effective moment based on the positive or negative sign of the predicted piston relative speed value. That is, whether the CDC damper is in the compression stroke or the recovery stroke at the effective moment. The damping force characteristics of the CDC damper are different in the two stroke directions, and its adjustable force range is also different. The subsequent mapping process needs to select the calibration data for the corresponding direction accordingly.
[0042] In step S4, based on the current, current change rate, comprehensive response delay, and current limit, the current achievable range of each damper at the moment of activation is calculated; the current achievable range, the corresponding predicted value of the piston relative speed, and the corresponding stroke direction at the moment of activation are mapped into four sets of achievable damping force ranges.
[0043] Traditional semi-active suspension control methods typically calculate the ideal damping force first, then cut it off to a feasible range when the force exceeds the shock absorber's capability. This post-calculation limitation disrupts the force distribution relationship between the four corners, leading to deviations in vehicle attitude control and frequent stagnation of the solenoid valve current near its limit. This embodiment, before distributing the force at the four corners, first determines the range of damping force that each CDC shock absorber can generate at the moment of activation, using this range as a hard constraint for subsequent vehicle-wide force distribution calculations. This range dynamically changes with piston relative speed, current, and stroke direction.
[0044] Specifically, please refer to Figure 2 , Figure 2 A flowchart illustrating the mapping of damping force ranges provided in an embodiment of this disclosure is shown, such as... Figure 2 As shown, in step S201, the current range that each damper can reach at the moment of activation is calculated based on the current, the rate of change of current, the overall response delay and the current limit.
[0045] The current of the solenoid valve coil is limited by the driving circuit capability and the coil inductance characteristics. Within the time window corresponding to the comprehensive response delay, it can only change from the current value to a certain range. The controller calculates the current range that each CDC damper can reach at the moment of activation based on the current, the upper limit of the current change rate, the comprehensive response delay, and the current limit.
[0046] Specifically, the current achievable range includes an upper current limit and a lower current limit. The upper current limit is determined by the current plus the product of the maximum rate of change of current rise and the overall response delay, while not exceeding the current limit allowed by the solenoid valve. ; The lower current limit is determined by subtracting the product of the maximum rate of current decrease and the overall response delay from the current, and is not lower than zero: ; in The first record for the controller The actual coil current currently being applied by each CDC shock absorber; and These are the maximum rate of change of current rising and the maximum rate of change of current falling, respectively, obtained by bench calibration from the drive circuit parameters and coil inductance. The maximum continuous current allowed by the solenoid valve is determined by the hardware specifications.
[0047] In step S202, the achievable range of each current, the corresponding predicted value of the relative velocity of the piston, and the stroke direction at the corresponding effective time are mapped to the achievable damping force range.
[0048] The damping force of the CDC shock absorber depends on both the coil current and the relative velocity of the piston. The correspondence between the two and the damping force is obtained through bench test calibration and stored in the controller in the form of a calibration mapping table. The calibration mapping table takes the current value and the relative velocity of the piston as inputs and outputs the corresponding damping force value. Since the damping force characteristics of the compression stroke and the recovery stroke are different, the calibration mapping table is stored separately according to the stroke direction.
[0049] In this embodiment, the upper limit and lower limit of damping force refer to the achievable damping force boundaries under the selected effective time travel direction and unified symbol convention. The damping force output of the calibration mapping table is unified according to the corresponding travel direction, so that the damping force boundary corresponding to the upper limit of current under the same travel direction is not lower than the damping force boundary corresponding to the lower limit of current. If other coordinate symbol conventions are used, the controller first converts the damping force value to the above unified symbol convention after looking up the table, and then determines the upper limit and lower limit of damping force.
[0050] For the For each CDC shock absorber, the controller first selects the corresponding calibration mapping table based on the travel direction at the corresponding activation time, and then sets the upper limit of the current. Input the predicted relative velocity of the corresponding piston into the calibration mapping table to find the upper limit of the damping force; input the lower limit of the current. Input the corresponding piston relative velocity prediction value into the calibration mapping table to find the lower limit of the damping force. The lower limit and upper limit of the damping force of the same CDC shock absorber constitute the range of achievable damping force for that shock absorber.
[0051] The achievable damping force range exhibits dynamic characteristics that vary with the operating point. When the absolute value of the piston relative velocity is large, the damping force adjustment range corresponding to the current changing from the lower limit to the upper limit is wide, and the shock absorber has a large adjustable range. When the piston relative velocity approaches zero, the damping force itself approaches zero, and regardless of how the current is adjusted, the adjustable range of the force is extremely limited. This is an inherent physical characteristic of the semi-active shock absorber as an energy-dissipating element; the magnitude of its damping force is always constrained by the relative motion velocity of the piston. Therefore, this embodiment establishes the achievable force range before allocation: if this constraint is not incorporated into the allocation process in advance, subsequent truncation will inevitably lead to the disruption of the coordination relationship of the forces between the four corners.
[0052] Optionally, the method also includes step S203, which involves adjusting the achievable damping force range based on temperature correction. When the oil temperature is below a preset threshold, the oil viscosity increases, causing the actual damping force under the same current to deviate from the room temperature calibration value. At this time, the controller reads the temperature correction coefficient from the temperature correction coefficient table based on the oil temperature estimate. This temperature correction coefficient table is established through bench calibration tests under different temperature conditions. The controller uses the temperature correction coefficient to correct the lookup result of the calibration mapping table, obtaining the corrected four sets of achievable damping force ranges. The corrected four sets of achievable damping force ranges replace the original four sets of achievable damping force ranges in the subsequent four target damping force solutions. The value of the preset threshold is determined based on the viscosity-temperature characteristics of the shock absorber oil used and is written into the controller parameter area during the calibration stage.
[0053] The above process is performed on the four CDC shock absorbers respectively, and finally outputs four sets of achievable damping force ranges. Each set includes a lower limit of damping force and an upper limit of damping force. Since these achievable damping force ranges are based on the effective time, they take into account the current response capability, piston speed prediction and stroke direction, so that the constraints on which the subsequent distribution calculation is based are consistent with the actual performance capability of the shock absorber, thereby reducing the deviation between the target force and the actual force from the root.
[0054] In step S5, the vehicle modal control target is generated based on the vehicle body's vertical velocity, pitch angular velocity, and roll angular velocity; the target damping force is solved using the achievable damping force range as a constraint and the vehicle modal control target as a reference input.
[0055] For details, please refer to Figure 3 , Figure 3 A flowchart illustrating the target damping force solution provided in an embodiment of this disclosure is shown, as follows: Figure 3 As shown, in step S301, the vehicle modal control target is generated based on the vehicle's vertical velocity, pitch angular velocity, and roll angular velocity.
[0056] The controller generates vehicle modal control targets based on the vehicle's vertical velocity, pitch angular velocity, and roll angular velocity obtained from the state estimation. These targets include vertical control targets, pitch control targets, and roll control targets.
[0057] The vertical control target is generated by the controller based on the vehicle's vertical velocity. Its control principle can adopt the concept of ceiling damping, that is, applying a damping force opposite to the direction of the vehicle's absolute velocity to suppress the vehicle's vertical vibration. The pitch control target is generated based on the pitch angular velocity and longitudinal acceleration, and is used to suppress the vehicle's nose sinking during braking and the vehicle's nose lifting during acceleration. The roll control target is generated based on the roll angular velocity and lateral acceleration, and is used to suppress the vehicle's roll during cornering. If the controller has already compensated for the lateral acceleration, then the roll control target and roll angular velocity estimation use the compensated lateral acceleration.
[0058] The three modal control targets mentioned above are only used as reference inputs at the vehicle level and passed to the subsequent force distribution. They are not directly converted into current commands for each shock absorber. Modal targets can be generated using methods such as ceiling control, floor control, or linear quadratic regulators. This embodiment does not limit the specific form.
[0059] In this embodiment, the vertical control target, pitch control target, and roll control target are all represented by target modal accelerations; wherein the vertical control target corresponds to the vehicle's vertical acceleration, the pitch control target corresponds to the pitch angle acceleration, and the roll control target corresponds to the roll angle acceleration; if the ceiling control, floor control, or LQR control law is used to generate equivalent vertical force, pitch moment, or roll moment, the controller converts them into the corresponding target modal accelerations according to the vehicle mass, moment of inertia about the transverse axis, and moment of inertia about the longitudinal axis, respectively.
[0060] In step S302, the target damping force is solved with the achievable damping force range as a constraint and the vehicle modal control target as a reference input.
[0061] Specifically, based on known parameters such as the vehicle's total mass, moment of inertia about the transverse axis, moment of inertia about the longitudinal axis, wheelbase, and track width, the contribution of the damping forces of the four CDC shock absorbers to the vehicle's vertical acceleration, pitch acceleration, and roll acceleration can be expressed as a linear superposition relationship. The four target damping forces are used as control variables to be determined in this relationship. The vehicle's geometric and inertial parameters are known coefficients. The controller uses this linear superposition relationship to map the four independent forces onto the three vehicle modal responses.
[0062] The controller calculates the modal deviations corresponding to the vertical, pitch, and roll control targets based on the aforementioned linear superposition relationship. When calculating these modal deviations, the contribution coefficients of the four target damping forces to the vertical, pitch, and roll modes can be multiplied by their corresponding modal contribution weights. These modal contribution weights are used to adjust the proportion of control input borne by each CDC damper in each modal direction, and their effect is reflected in… , and The calculation is as follows. Modal deviation refers to the difference between the vehicle body's modal acceleration and the corresponding modal control target, given four target damping forces.
[0063] The objective function of the quadratic programming (QP) is constructed by the weighted sum of squares of modal deviation, tire normal load variation, and coil current variation: ; in , , These are the three modal deviations: vertical, pitch, and roll, which are the deviations of the vehicle's vertical acceleration, pitch acceleration, and roll acceleration relative to the corresponding target modal acceleration. For the first The change in normal load on each wheel's tires; For the first The change in coil current of each CDC damper, i.e., the change in target current relative to the current; when constructing the quadratic programming objective function, the controller, based on the calibration mapping table corresponding to the current operating point, interpolates or locally linearizes the back lookup relationship between candidate target damping force and coil current to obtain the estimated target current value corresponding to the candidate target damping force, and calculates accordingly. .
[0064] in , , These are the weighting coefficients corresponding to the three modal deviations, reflecting the vehicle's relative emphasis on comfort, longitudinal attitude stability, and roll control. They are predetermined through vehicle calibration tests and stored in the controller calibration parameter area. In some embodiments, the above three weights can be dynamically adjusted according to driving conditions; for example, they can be increased when the absolute value of longitudinal acceleration exceeds the calibrated braking judgment threshold. To enhance pitch control, the lateral acceleration is increased when its absolute value exceeds the calibrated turning threshold. To enhance roll control, the operating condition is determined based on a combination of longitudinal acceleration, lateral acceleration, and vehicle speed.
[0065] in This is a weighting coefficient corresponding to the change in tire normal load, determined during the vehicle calibration phase. It is used to constrain tire runout while adjusting vehicle body posture. This is the weighting coefficient corresponding to the change in coil current. Its value is usually smaller than the modal deviation weight. It is used to penalize excessive current jumps during adjacent control cycles and reduce valve body noise and force step sensation.
[0066] All the above weighting coefficients are predetermined and written into the controller calibration parameter area during the vehicle tuning stage before mass production application. They can also be modified based on subjective evaluation and objective indicators when the controller parameters are updated. In addition, to enable the above different physical quantities to be compared in the same objective function, each weighting coefficient includes the normalization scale or dimensional conversion factor of the corresponding physical quantity, or the controller first... , , , and Each parameter is normalized according to a pre-calibrated reference scale and then substituted into the objective function. The reference scale is determined during the vehicle calibration stage and stored in the controller calibration parameter area.
[0067] In one embodiment, the constraints for solving the four target damping forces include the following four items: First, there is a constraint on the range of achievable damping forces: each target damping force is within the corresponding range of achievable damping forces, that is, not lower than the lower limit of damping force and not higher than the upper limit of damping force. This constraint directly uses the output of the aforementioned steps to ensure that the distribution result is within the range of forces that each shock absorber can actually generate at the moment of activation.
[0068] Second, the dissipative constraint: the product of each target damping force and the corresponding piston relative velocity prediction value is not less than zero; the semi-active shock absorber can only consume mechanical energy and cannot inject energy into the suspension system. This constraint ensures that the direction of the damping force and the direction of relative motion meet the energy dissipation condition.
[0069] Third, the current change rate constraint: the change in current of each coil shall not exceed the maximum change in one control cycle; this constraint, based on the current reachability range constraint, further limits the current jump amplitude in a single control cycle, so as to avoid the solution result being within the force range but requiring the current to change too drastically.
[0070] Fourth, safety constraints: When a braking state signal or a vehicle stability control system request signal is triggered, the controller sets a safe lower limit for the damping force of the CDC shock absorber corresponding to the request signal; wherein the CDC shock absorber corresponding to the request signal is identified by the wheel, axle, or body lateral control object identifier in the request signal; when the request signal does not carry a single CDC shock absorber identifier, the controller interprets the request as a safety lower limit request for the corresponding axle, the corresponding body side, or all four CDC shock absorbers according to a pre-calibrated safety strategy; this safety lower limit is determined by the vehicle safety calibration, and its priority is higher than the modal control target to ensure handling stability under extreme braking or instability conditions; when the safety lower limit exists simultaneously with the achievable damping force range constraint or dissipative constraint, the controller first performs a feasibility check on the safety lower limit based on the achievable damping force range and dissipative constraint obtained in the aforementioned steps. If the calibrated safety lower limit is higher than the corresponding damping force upper limit, then the upper limit of the damping force that the CDC damper can achieve at the current effective moment shall be used as the actual safety lower limit to participate in the solution; the safety lower limit has higher priority than the modal control target, but not higher than the achievable damping force range constraint and dissipation constraint.
[0071] In one embodiment, the variables to be solved in the above quadratic programming problem are four target damping forces. The total number of constraints is finite, and the problem size is relatively small. The controller can use the effective set method to complete the solution within one control cycle. Specifically, the effective set method involves determining which inequality constraints are active in each iteration (i.e., the variables to be solved happen to be on the constraint boundaries). These active constraints are treated as equality constraints. Unconstrained or equality-constrained subproblems are solved for the remaining variables. The Lagrange multipliers are used to determine whether the set of active constraints needs to be increased or decreased until the optimality condition is met. In some embodiments, an online solver based on a fixed number of iterations can also be used to provide an approximate optimal solution, further reducing computation time. This will not be elaborated further in this embodiment.
[0072] After the solution is completed, the controller obtains the four target damping forces for the current cycle. Since the range of achievable damping forces has been used as a hard constraint in the solution, when the adjustable space of a certain corner CDC damper is insufficient due to the piston relative speed being too low or the current being close to the limit, the solver automatically distributes the control quantity that the corner cannot bear to the other dampers that still have adjustment margin, under the premise of satisfying all constraints, and re-balances among the modal objectives. The cross-angle distribution is naturally generated by the optimization solution process.
[0073] In step S6, the coil current command is obtained by reverse lookup based on the target damping force and the predicted value of the piston relative velocity, and then output to the corresponding solenoid valve drive circuit.
[0074] Specifically, please refer to Figure 4 , Figure 4 A flowchart illustrating the current command lookup and output process provided in an embodiment of this disclosure is shown, such as... Figure 4As shown, in step S401, the coil current command is obtained by reverse lookup based on the target damping force and the predicted value of the piston relative velocity.
[0075] For each CDC damper, the controller performs a reverse lookup in the corresponding calibration mapping table based on its target damping force, the corresponding predicted piston relative velocity, and the stroke direction at the corresponding activation time. The calibration mapping table stores the forward relationship between current and piston relative velocity to damping force. The reverse lookup process involves interpolating the required current value, known as the initial coil current command, given the target damping force and the predicted piston relative velocity. This reverse lookup process is related to the calculation steps mentioned above. The current estimation is based on the same criteria, but the output here is the final current initial command after the solution is completed.
[0076] In step S402, a first-order low-pass filter is applied to the initial coil current command, and the filtered command is output to the corresponding solenoid valve drive circuit for execution. Under certain operating conditions, the calibration mapping table exhibits high sensitivity to current in certain regions due to damping force; small current changes can cause significant force changes. The accuracy of the lookup is limited by the mapping table resolution, potentially leading to jitter in the initial current command between adjacent cycles. To address this, the controller applies a first-order low-pass filter to the initial coil current command. The filter time constant is selected based on the inherent response characteristics of the solenoid valve to smooth out current fluctuations caused by insufficient table resolution, resulting in the final coil current command. The filter coefficient of the first-order low-pass filter is between 0 and 1. The filtered coil current command is then limited by current limits and the maximum change in a single cycle to ensure it does not exceed the current achievable range determined in the preceding steps. The controller then outputs the coil current command to the corresponding solenoid valve drive circuit for execution.
[0077] In some embodiments, the controller monitors whether the target damping force of each CDC damper continuously approaches the boundary of the achievable damping force range. Within a preset number of consecutive cycles, if the difference between the target damping force of any CDC damper and the upper or lower limit of the corresponding achievable damping force range is less than a preset margin threshold, the controller determines that the damper is in a continuous edge-fitting state. The preset margin threshold is a pre-calibrated fixed value used to define whether the target force has sufficiently approached the adjustable boundary; the preset number of cycles is also a calibration parameter, indicating how many consecutive cycles of edge-fitting are required for the system to determine that the adjustment capability is insufficient.
[0078] When a CDC damper is detected to be in a state of continuous contact with the edge, the controller decreases the modal contribution weight corresponding to that CDC damper in the quadratic programming objective function of the next control cycle, and increases the modal contribution weights corresponding to the other CDC dampers. The modal contribution weight is a local adjustment coefficient used to correct the contribution coefficients of the four target damping forces to each modal deviation in the preceding steps. It characterizes the local adjustment coefficient of the control proportion undertaken by each damper in each modal direction. Its initial value is determined during the calibration phase based on the vehicle's geometric symmetry, and its value ranges from 0 to 1.
[0079] When the weight of a corner damper decreases due to continuous contact with the edge, its proportion in modal control decreases, while the weights of other corner points increase accordingly. This causes the system to actively transfer the control quantity from dampers with insufficient capacity to those with remaining capacity. Specifically, the controller reduces the modal contribution weight of the CDC damper in continuous contact with the edge with a pre-calibrated weight adjustment step size, and distributes the weight increment in the same modal direction to the other CDC dampers according to their current adjustable capacity ratio. The adjusted modal contribution weight is limited to between 0 and 1, and the modal contribution weights of the four CDC dampers in the same modal direction are normalized to keep their relative contribution ratios comparable.
[0080] For example, when a vehicle passes through a lateral joint in a curve, the outer front wheel CDC shock absorber may continuously approach its damping force limit due to the combined effects of roll control requirements and road impact. After the controller recognizes that the corner is in a close-to-the-edge state, it reduces the modal contribution weight of the shock absorber in the roll and pitch directions, while increasing the weight of the outer rear wheel and the inner wheel. This redistributes the burden of vehicle attitude control among corners with sufficient margin, preventing the current of the outer front wheel solenoid valve from remaining near the saturation value for a long time.
[0081] In some embodiments, after each control cycle is completed, the controller may correct the local deviation of the solenoid valve's overall response time and the calibration mapping table in the current operating range.
[0082] Specifically, for correcting the overall response time of the solenoid valve, the controller compares the delay between the moment the current command is issued and the moment when an observable change occurs in the vehicle body response. An observable change in the vehicle body response refers to a change in at least one of the vehicle body's vertical acceleration, pitch angular velocity, or roll angular velocity exceeding a pre-calibrated response change threshold. If this delay deviates continuously from the currently used overall response delay within a consecutive preset correction period, the overall response time of the solenoid valve is updated using recursive least squares (RLS) with a forgetting factor. Specifically, each time a new set of data is obtained, the parameter estimation results are updated based on the deviation between the current estimate and the actual observed values. The forgetting factor allows the algorithm to pay more attention to recent data. The forgetting factor ranges from 0 to 1; the closer it is to 1, the more historical data is retained and the smoother the update. The specific value is determined during the calibration phase based on the parameter stability requirements.
[0083] For local corrections to the calibration map, the controller estimates the deviation between the calibration value and the actual value near the current operating point based on the relationship between the target damping force, the actual execution current, and the vehicle body response, and updates it using the same recursive least squares method. This correction only takes effect within a small neighborhood of the current operating point and does not change the calibration values in other areas of the map. The small neighborhood is determined by the calibration map grid containing the current current, the predicted piston relative speed, and the stroke direction, as well as its adjacent grids.
[0084] The correction range is limited by a preset upper limit of the correction range; the upper limit of the correction range is determined based on the bench calibration repeatability error and the control safety margin and stored in the controller calibration parameter area; when an occasional large impact occurs on the road surface, the transient response deviation will not be mistakenly attributed to the change of the shock absorber parameters due to the attenuation effect of the forgetting factor and the limitation of the correction range, thereby maintaining the stability of the parameter estimation; the corrected result is used in the next control cycle.
[0085] Through the embodiments disclosed herein, the overall vehicle damping distribution is constrained by the actual performance capability of each CDC shock absorber at the moment of activation during the solution stage. The target damping force is always within the achievable range, avoiding the misalignment of the four-corner force distribution caused by post-processing truncation. Under complex conditions such as corner braking, joint impact, and continuous small undulations, when the adjustment capability of a certain corner shock absorber is insufficient, the secondary programming solution process automatically transfers the control quantity to the corner point with sufficient margin, thereby reducing the control deviations of vehicle pitch, roll, and vertical control, and suppressing the saturation and sudden change phenomena of solenoid valve current.
[0086] Please see Figure 5 , Figure 5 This is a structural block diagram of an intelligent collaborative control system for automotive shock absorbers provided in an embodiment of this application. Figure 5 As shown, the system includes: The signal acquisition and state estimation module 501 is used to acquire vehicle sensor signals and read the current, and estimate the vehicle body vertical speed, pitch angular velocity, roll angular velocity and shock absorber piston relative speed; The comprehensive response delay determination module 502 is used to determine the comprehensive response delay of the shock absorber based on the calculated communication delay and the comprehensive response time of the solenoid valve. The piston speed prediction module 503 is used to extrapolate the corresponding piston relative speed to the effective time based on each comprehensive response delay, obtain the piston relative speed prediction value, and determine the stroke direction at the corresponding effective time. The module 504, which can determine the damping force range, is used to calculate the current range that each shock absorber can achieve at the moment of activation based on the current, the rate of change of current, the comprehensive response delay and the current limit; and to map each current range, the corresponding predicted value of the piston relative speed and the corresponding stroke direction at the moment of activation into the range of achievable damping force. The target damping force solving module 505 is used to generate the vehicle modal control target based on the vehicle's vertical velocity, pitch angular velocity, and roll angular velocity; and to solve for the target damping force by using the achievable damping force range as a constraint and the vehicle modal control target as a reference input. The current command output module 506 is used to obtain the coil current command based on the predicted values of the target damping force and the piston relative speed, and output it to the corresponding solenoid valve drive circuit.
[0087] Each processing unit and / or module in the embodiments of this application can be implemented by an analog circuit that implements the functions described in the embodiments of this application, or by software that executes the functions described in the embodiments of this application.
[0088] Based on the same inventive concept, this application also provides an electronic device, the method corresponding to which can be the method in the foregoing embodiments, and its problem-solving principle is similar to that method. For example... Figure 6 As shown, Figure 6 This is a schematic block diagram of an electronic device provided in an embodiment of the present disclosure. The device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the methods and / or technical solutions of the foregoing embodiments of the present application.
[0089] In particular, the methods and / or embodiments in this application can be implemented as computer software programs. For example, the embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowchart. When the computer program is executed by a processor, it performs the functions defined in the methods of this application.
[0090] Another embodiment of this application provides a storage medium storing computer program instructions thereon, which can be executed by a processor to implement the methods and / or technical solutions of any one or more embodiments of this application.
[0091] In the above embodiments, the descriptions of each embodiment have different focuses. Parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments. The above descriptions are merely preferred embodiments of this application and explanations of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by specific combinations of the above technical features, but should also cover other technical solutions formed by arbitrary combinations of the above technical features or their equivalent features without departing from the inventive concept.
Claims
1. An intelligent collaborative control method for automobile shock absorbers, characterized in that, include: Collect vehicle sensor signals and read the current to estimate the vehicle's vertical speed, pitch speed, roll speed, and the relative speed of the shock absorber pistons; The overall response delay of the shock absorber is determined based on the calculated communication delay and the overall response time of the solenoid valve. Using the overall response delay as a time reference, the corresponding piston relative velocity is extrapolated to the effective time to obtain the predicted value of piston relative velocity, and the stroke direction at the corresponding effective time is determined. Based on the current, current change rate, overall response delay, and current limit, calculate the current range that each damper can achieve at the moment of activation; map each current range, the corresponding predicted piston relative velocity, and the corresponding stroke direction at the moment of activation to the range of achievable damping force. The vehicle modal control target is generated based on the vehicle's vertical velocity, pitch velocity, and roll velocity; the target damping force is solved using the achievable damping force range as a constraint and the vehicle modal control target as a reference input. The coil current command is obtained by reverse lookup based on the predicted values of the target damping force and piston relative velocity, and then output to the corresponding solenoid valve drive circuit.
2. The method of claim 1, wherein, The vehicle sensor signals include vehicle vertical acceleration, longitudinal acceleration, lateral acceleration, yaw rate, steering angle, vehicle speed, suspension travel, wheel speed, braking status signals, and vehicle stability control system request signals. The controller estimates the vehicle vertical speed based on the rate of change of the vehicle vertical acceleration and suspension travel, estimates the pitch rate and roll rate based on the longitudinal acceleration, lateral acceleration, wheelbase, and track width, and obtains the piston relative speed based on the rate of change of the suspension travel.
3. The method of claim 1, wherein, The determination of the overall response delay of the shock absorber includes: reading the overall response time of the solenoid valve from the calibration lookup table; the calibration lookup table is indexed by the current current, the direction of current change and the oil temperature estimate, and the calculated communication delay is added to the overall response time of the corresponding solenoid valve to obtain the overall response delay of the corresponding shock absorber.
4. The method of claim 1, wherein, The process of obtaining the piston relative speed prediction value includes: calculating the speed change rate based on the piston relative speed of the current control cycle and the piston relative speed of the previous control cycle; multiplying the speed change rate by the corresponding comprehensive response delay to obtain the speed extrapolation; and adding the speed extrapolation to the piston relative speed of the current control cycle to obtain the corresponding piston relative speed prediction value.
5. The method of claim 1, wherein, The current current is the coil current currently actually executed by each shock absorber as recorded by the controller; the current reachable range includes an upper current limit and a lower current limit. The upper current limit is determined by the current current, the maximum rate of change of current rise, the comprehensive response delay, and the current limit value. The lower current limit is determined by the current current, the maximum rate of change of current fall, and the comprehensive response delay.
6. The method of claim 5, wherein, The process of mapping each current reachable range, the corresponding piston relative velocity prediction value, and the corresponding stroke direction at the effective time to an achievable damping force range includes: selecting a calibration mapping table according to the stroke direction at the corresponding effective time; inputting the corresponding upper limit of current and the corresponding piston relative velocity prediction value into the calibration mapping table to obtain the upper limit of damping force; inputting the corresponding lower limit of current and the corresponding piston relative velocity prediction value into the calibration mapping table to obtain the lower limit of damping force; and forming a corresponding achievable damping force range by the lower limit and upper limit of damping force of the same shock absorber.
7. The method of claim 1, wherein, The process of solving for the target damping force includes: establishing a linear superposition relationship between the damping force and the vehicle body modal response, and using the target damping force as the control variable to be determined; calculating the modal deviations corresponding to the vertical control target, pitch control target, and roll control target based on the linear superposition relationship; and constructing a quadratic programming objective function using the weighted sum of squares of the modal deviation, the change in tire normal load, and the change in coil current.
8. The method of claim 7, wherein, The constraints for solving the target damping force include: each target damping force is within the corresponding achievable damping force range; the product of each target damping force and the corresponding piston relative velocity prediction value is not less than zero; the change in current of each coil does not exceed the maximum change within one control cycle; and when the braking state signal or the vehicle stability control system request signal is triggered, a safe lower limit for damping force is set for the shock absorber corresponding to the request signal.
9. The method of claim 1, wherein, The reverse lookup to obtain the coil current command includes: interpolating the initial coil current command in the corresponding calibration mapping table based on each target damping force, the corresponding predicted value of the piston relative velocity, and the corresponding stroke direction at the effective time; applying a first-order low-pass filter to the initial coil current command to obtain the coil current command, and outputting the coil current command to the corresponding solenoid valve drive circuit.
10. An intelligent collaborative control system for an automobile shock absorber, characterized in that, include: The signal acquisition and state estimation module is used to acquire vehicle sensor signals and read the current, and estimate the vehicle's vertical speed, pitch speed, roll speed and the relative speed of the shock absorber pistons; The comprehensive response delay determination module is used to determine the comprehensive response delay of the shock absorber based on the calculated communication delay and the comprehensive response time of the solenoid valve. The piston speed prediction module is used to extrapolate the corresponding piston relative speed to the effective time based on each comprehensive response delay, obtain the piston relative speed prediction value, and determine the stroke direction at the corresponding effective time. The module for determining the damping force range is used to calculate the current achievable range of each shock absorber at the moment of activation based on the current, current change rate, comprehensive response delay, and current limit; and to map each current achievable range, the corresponding predicted value of the piston relative velocity, and the corresponding stroke direction at the moment of activation into the achievable damping force range. The target damping force solution module is used to generate the vehicle modal control target based on the vehicle's vertical velocity, pitch angular velocity, and roll angular velocity; and to solve for the target damping force by using the achievable damping force range as a constraint and the vehicle modal control target as a reference input. The current command output module is used to obtain the coil current command based on the predicted values of the target damping force and the piston relative speed, and output it to the corresponding solenoid valve drive circuit.