Variable stiffness and damping switching control method for vehicle intelligent suspension under impact conditions

Abstract

The present application relates to the technical field of suspension control methods, and in particular to a vehicle intelligent suspension variable stiffness and variable damping switching control method under impact conditions, which includes building an impact condition database, acquiring real-time vehicle information, identifying driving conditions, and variable stiffness and variable damping control steps; selecting a corresponding controller according to different impact conditions to perform variable stiffness and variable damping switching control, thereby improving the efficiency of reducing response acceleration and shortening the time it takes for the vehicle to reach stability; and building a magnetorheological-air suspension variable stiffness and variable damping switching control system under impact conditions based on the vehicle intelligent suspension variable stiffness and variable damping switching control method. The present application has the effect of effectively attenuating the vehicle's response acceleration, allowing the vehicle to quickly reach a stable state, and improving ride comfort.

Description

Technical Field

[0001] The present application relates to the technical field of suspension control methods, and in particular to a vehicle intelligent suspension variable stiffness and variable damping switching control method under impact conditions. Background Art

[0002] Impact conditions generally include passing obstacles at high speed, road bumps, and other situations. Under impact conditions, the stability of the vehicle will be affected, the passenger comfort will be greatly reduced, and may even cause safety accidents.

[0003] Currently, variable damping control is commonly used to address impact conditions. This method controls the suspension system's response by adjusting the damping coefficient. When a vehicle is impacted, the suspension begins to increase damping, dissipating energy and stabilizing the vehicle body.

[0004] However, at the beginning of the impact, the relative speed and absolute speed of the suspension are opposite to each other. At this time, increasing the damping cannot output control force, and therefore cannot respond to changes in the impact load. As a result, sufficient force cannot be provided in time to reduce the response acceleration of the vehicle body at the beginning of the impact, and may even cause the suspension system to deteriorate. This prolongs the time it takes for the vehicle to reach stability, affects the control of vehicle vibration, and thus reduces ride comfort. Summary of the Invention

[0005] In order to effectively attenuate the response acceleration of the vehicle and enable the vehicle to quickly reach a stable state, the present application provides a vehicle intelligent suspension variable stiffness and variable damping switching control method under impact conditions.

[0006] In a first aspect, the present application provides a method for controlling the variable stiffness and variable damping switching of a vehicle intelligent suspension under impact conditions, which adopts the following technical solutions:

[0007] A vehicle intelligent suspension variable stiffness and variable damping switching control method under impact conditions comprises the following steps:

[0008] Build an impact condition database: including different impact conditions and corresponding vehicle driving parameters;

[0009] Obtain real-time vehicle information: collect vehicle driving parameters in real time;

[0010] Driving condition identification: By monitoring and analyzing the vehicle's real-time driving parameters and comparing them with the impact condition database, the vehicle's current operating condition is determined. If the vehicle is in an impact condition, variable stiffness and damping control is implemented.

[0011] Variable stiffness and variable damping control: The vehicle is first subjected to variable stiffness control according to the impact working conditions. After a period of time, the vehicle is subjected to variable damping control according to the impact working conditions. The stiffness is changed by the air spring, and the damping is changed by the magnetorheological damper.

[0012] By adopting the above technical solution, an impact condition database is first established, and different impact conditions and corresponding vehicle driving parameters are pre-stored. Then, real-time vehicle information is obtained, and the real-time collected vehicle driving parameters are matched with the vehicle driving parameters in the impact condition database, thereby realizing accurate and rapid identification of the vehicle driving condition. Once it is identified that the vehicle is in an impact condition, variable stiffness and variable damping control are executed. First, variable stiffness control is performed on the vehicle according to the impact condition to attenuate the vehicle's early response acceleration. Then, after a period of time, variable damping control is performed on the vehicle according to the impact condition to attenuate the vehicle's later response acceleration and enable the vehicle to quickly reach a stable driving state. Reducing the response acceleration can reduce the vibration felt by passengers, thereby improving ride comfort, and also helps to maintain the stability and controllability of the vehicle, thereby improving driving safety.

[0013] Optionally, in the variable stiffness and variable damping control steps, a fuzzy control algorithm is used to control the variable stiffness controller and the variable damping controller, wherein the input of the variable stiffness controller includes the relative displacement and relative speed of the suspension, the input of the variable damping controller includes the relative speed and absolute speed of the suspension, and the outputs of the variable stiffness controller and the variable damping controller are both execution control forces.

[0014] By adopting the above technical solution and using a fuzzy control algorithm to design a variable stiffness controller and a variable damping controller, the controllers can respond quickly and accurately, outputting control forces based on the real-time vehicle state, and dynamically adjusting the stiffness and damping of the vehicle suspension system to cope with complex impact conditions and vehicle state changes. Since the changes in the stiffness and damping of the vehicle suspension system are related to the vehicle load, road conditions, and vehicle speed, the vehicle speed changes in real time during driving and can quickly reflect the vehicle's motion state. However, the vehicle load and road conditions change relatively slowly, and measuring and processing this data requires a certain amount of time, resulting in a delay in the suspension system's response. Moreover, compared with vehicle load and road conditions, vehicle speed is a parameter that is easier to measure. Therefore, the introduction of parameters related to vehicle speed, such as relative displacement, relative velocity, and absolute velocity, provides comprehensive data support for controller design, enabling the controller to more accurately determine the vehicle's current motion state and force conditions, thereby selecting a more appropriate control strategy and achieving fine-tuning of the vehicle suspension system. This not only improves ride comfort, but also extends the service life of the vehicle suspension system to a certain extent and reduces maintenance costs.

[0015] Optionally, in the variable stiffness and variable damping control step, when the relative speed of the suspension is not opposite to the absolute speed, the variable stiffness control is switched to the variable damping control; wherein the relative speed is the speed of the sprung mass relative to the unsprung mass.

[0016] By adopting the above technical solution, since the magnetorheological damper for variable damping control is a semi-active device, its control needs to follow the semi-active control conditions; in the early stage of the impact condition, that is, when the relative speed and the absolute speed of the suspension are reversed, variable damping control cannot be performed to reduce the body response acceleration, and variable stiffness control has a better control effect on the body response acceleration. When the relative speed and the absolute speed of the suspension are not reversed, variable damping control can more effectively attenuate the body response acceleration, so that the system reaches a stable state faster; therefore, in the later stage of the impact condition, that is, when the relative speed and the absolute speed of the suspension are not reversed, switching the variable stiffness control to variable damping control can improve ride comfort and safety, and bring passengers a smoother and more comfortable driving experience.

[0017] Optionally, in the variable stiffness and variable damping control step, when the relative speed of the suspension is equal to zero for the first time, the variable stiffness control is switched to the variable damping control.

[0018] By adopting the above technical solution, when the relative speed of the suspension is equal to zero for the first time, that is, when the vehicle is at the dividing line between the early and late stages of the impact condition, the variable stiffness control is switched to the variable damping control. At this time, the suspension system is in a relatively stable state, which can avoid adjustments during the dynamic response process of the suspension system, thereby reducing excessive dynamic response caused by improper adjustment, and can better balance the vehicle's handling and comfort, providing passengers with a smoother ride experience.

[0019] Optionally, a control exit step is provided after the variable stiffness and variable damping control step;

[0020] Control exit: Set the response acceleration threshold; when the vehicle is in an impact condition, if the response acceleration is less than the response acceleration threshold within a period of time, it is determined that the vehicle has exited the impact condition and the variable damping control ends.

[0021] By adopting the above technical solution, a control exit step is set after the variable stiffness and variable damping control step, and a response acceleration threshold is set to determine whether the vehicle is still in an impact condition. If the response acceleration is less than the set response acceleration threshold within a period of time, it is determined that the vehicle has exited the impact condition and the variable damping control is terminated. This effectively avoids unnecessary control adjustments after the vehicle has stabilized or the impact condition has ended, thereby improving the control efficiency and stability of the suspension system. Since the response acceleration is a fluctuating value within the impact condition, it is necessary to compare the response acceleration over a period of time with the response acceleration threshold.

[0022] Optionally, in the step of obtaining real-time vehicle information, the road condition ahead of the vehicle in the direction of travel is also identified to obtain road condition data;

[0023] In the driving condition identification step, the road condition data is also compared with the impact condition database to obtain the current vehicle condition.

[0024] By adopting the above technical solution, the road condition ahead of the vehicle's driving direction is identified, and the identified road condition data is matched with the information in the impact condition database, thereby achieving accurate and rapid identification of the vehicle condition ahead of the vehicle's driving direction.

[0025] Optionally, a control exit step is provided after the variable stiffness and variable damping control step;

[0026] Control exit: When the vehicle is in an impact condition, if the road condition for a certain distance ahead is not an impact condition, it is determined that the vehicle has exited the impact condition and the variable damping control is terminated.

[0027] By adopting the above technical solution, the road condition ahead of the vehicle in the direction of travel during the impact condition is identified. If the road condition for a certain distance ahead is not an impact condition, it is determined that the vehicle has exited the impact condition and the variable damping control is terminated. This method can adjust the control method in advance to avoid switching after the impact condition ends, which causes control lag, and is beneficial to improving the response speed of the suspension system, so that the vehicle can maintain optimal handling and comfort under different conditions.

[0028] In a second aspect, the present application provides a variable stiffness and variable damping switching control system for a magnetorheological-air suspension under impact conditions, which adopts the following technical solutions:

[0029] A variable stiffness and variable damping switching control system for a magnetorheological-air suspension under impact conditions, comprising:

[0030] Database: used to store different impact conditions and corresponding vehicle driving parameters; vehicle driving parameters can be obtained through sensors or historical data;

[0031] Vehicle real-time information acquisition module: used to collect vehicle driving parameters in real time; vehicle driving parameters are acquired in real time through sensors;

[0032] Driving condition identification module: The input end is connected to the output end of the vehicle real-time information acquisition module and the database; it is used to monitor and analyze the real-time driving parameters of the vehicle and compare them with the impact condition database to determine the current vehicle condition; if the vehicle is in an impact condition, a signal is sent to the controller module;

[0033] Controller module: The input end is connected to the output end of the driving condition identification module; it is used to control the variable stiffness shock absorber and the variable damping shock absorber according to the preset control algorithm for different impact conditions;

[0034] Variable stiffness shock absorber: The input end is connected to the output end of the controller module and is used to adjust the execution control force and the stiffness of the suspension system;

[0035] Variable damping shock absorber: The input end is connected to the output end of the controller module and is used to adjust the execution control force and control the damping of the suspension system.

[0036] In a third aspect, the present application provides a magnetorheological-air suspension vehicle, which adopts the magnetorheological-air suspension system provided by the present application.

[0037] In summary, this application includes at least one of the following beneficial technical effects:

[0038] 1. This application builds an impact condition database, pre-stores different impact conditions and corresponding vehicle driving parameters, then obtains real-time vehicle information, and matches the real-time collected vehicle driving parameters with the vehicle driving parameters in the impact condition database, thereby realizing accurate and rapid identification of the vehicle driving condition; once it is identified that the vehicle is in an impact condition, variable stiffness and variable damping control are executed, firstly, variable stiffness control is performed on the vehicle according to the impact condition to attenuate the early response acceleration of the vehicle, and then after a period of time, variable damping control is performed on the vehicle according to the impact condition to attenuate the late response acceleration of the vehicle and enable the vehicle to quickly reach a stable driving state; reducing the response acceleration can reduce the vibration felt by passengers, thereby improving ride comfort, and also helps to maintain the stability and controllability of the vehicle, thereby improving driving safety.

[0039] 2. This application switches variable stiffness control to variable damping control when the relative speed of the suspension is equal to zero for the first time, that is, when the vehicle is at the dividing line between the early and late stages of the impact condition. At this time, the suspension system is in a relatively stable state, which can avoid adjustments during the dynamic response process of the suspension system, thereby reducing excessive dynamic response caused by improper adjustment, and can better balance the vehicle's handling and comfort, providing passengers with a smoother ride experience.

[0040] 3. This application is provided with a control exit step, and adopts the method of setting a response acceleration threshold to determine whether the vehicle is still in an impact condition. If the response acceleration is less than the set response acceleration threshold within a period of time, it is determined that the vehicle has exited the impact condition and the variable damping control is ended; it effectively avoids unnecessary control adjustments after the vehicle has stabilized or the impact condition has ended, thereby improving the control efficiency and stability of the suspension system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a flow chart of Example 1 of the present application;

[0042] Figure 2 This is a flow chart of Example 2 of the present application;

[0043] Figure 3 is a flow chart of Example 3 of the present application;

[0044] Figure 4 is a flow chart of Example 4 of the present application;

[0045] Figure 5 is a flow chart of Example 5 of the present application;

[0046] Figure 6 This is a flowchart of Example 6 of the present application. DETAILED DESCRIPTION

[0047] The following combination Figures 1 to 6 This application is described in further detail.

[0048] This embodiment discloses a variable stiffness and variable damping switching control method for a vehicle intelligent suspension under impact conditions.

[0049] Example 1: Reference Figure 1 The vehicle intelligent suspension variable stiffness and variable damping switching control method under impact conditions includes the following steps:

[0050] Build an impact condition database: including different impact conditions and corresponding vehicle driving parameters; impact conditions refer to the vehicle response state when the vehicle passes through uneven roads such as potholes, bumps, speed bumps, slopes, bulges, etc., for example: impact conditions are divided into levels according to different vehicle response states, such as mild, moderate, severe, extreme, etc.; in other embodiments, they can also be divided into level one, level two, level three, etc.; the corresponding vehicle driving parameters include key information such as vehicle speed, acceleration, relative speed, relative displacement, etc., and the vehicle driving parameters can be obtained through sensors installed on the suspension or historical data.

[0051] In the process of building an impact condition database, it is also necessary to consider the responses of different vehicle models and different suspension systems to impact conditions, so that the database has higher accuracy and pertinence; the establishment of the database needs to be based on a large amount of experimental data and simulation analysis to ensure the accuracy and reliability of the data.

[0052] Obtaining real-time vehicle information: real-time collection of vehicle driving parameters; the vehicle driving parameters that need to be collected are consistent with the parameters required for building an impact working condition database. In the embodiment of the present application, the vehicle driving parameters include key information such as vehicle speed, acceleration, relative speed, relative displacement, and road conditions. In other embodiments, it can also be vehicle load, impact direction, and buffer performance; this information can be obtained through sensors installed on the suspension or simulation experiments. The sensors include acceleration sensors, displacement sensors, speed sensors, wheel sensors, etc.

[0053] Driving condition identification: By monitoring and analyzing the vehicle's real-time driving parameters and comparing them with the impact condition database, the vehicle's current condition is determined; if the vehicle is in an impact condition, variable stiffness and variable damping control is implemented; the impact condition database contains characteristic parameters of various impact conditions. When the vehicle's driving parameters match a certain impact condition characteristic parameter in the impact condition database, it can be determined that the vehicle is currently in that impact condition; when the vehicle is in an impact condition, variable stiffness and variable damping control is implemented.

[0054] Variable stiffness and variable damping control: The vehicle is first subjected to variable stiffness control according to the impact conditions. After a period of time, the vehicle is subjected to variable damping control according to the impact conditions. Controlling the air spring can change the stiffness, and controlling the magnetorheological damper can change the damping.

[0055] Since the impact time of the impact condition is short and the energy is large, a single variable damping control or variable stiffness control of the suspension cannot effectively suppress the impact, and the magnetorheological damper is a semi-active device, and its control needs to follow the semi-active control conditions. In the early stage of the impact condition, that is, when the relative speed and absolute speed of the suspension are reversed, variable damping control cannot be performed to reduce the body response acceleration. At this time, the effect of variable stiffness control is significantly better than variable damping control. Variable stiffness control can better attenuate the first response acceleration peak, while variable damping control can better attenuate the second response acceleration peak and make the system reach stability faster.

[0056] The implementation principle of Example 1 of the present application is as follows: first, by building an impact condition database, various impact conditions and their corresponding vehicle driving parameters are pre-stored, and then the vehicle driving parameters collected in real time are compared with the parameters in the impact condition database to achieve accurate and rapid identification of the vehicle driving condition; when it is detected that the vehicle is in an impact condition, a variable stiffness and variable damping control method is immediately adopted to respond; in the early stage of impact excitation, variable stiffness control is adopted to reduce the initial response acceleration of the vehicle, and after a period of time, variable damping control is adopted to reduce the later response acceleration of the vehicle, so that the vehicle can quickly return to a stable driving state, and by attenuating the vehicle body response acceleration, the vehicle vibration felt by the passengers is reduced, thereby improving the riding comfort.

[0057] Example 2: This example is similar to Example 1, except that:

[0058] Reference Figure 2 In the controller design step, the fuzzy control algorithm is used to control the variable stiffness controller and the variable damping controller. The input of the variable stiffness controller includes the relative displacement and relative velocity of the suspension, and the input of the variable damping controller includes the relative velocity and absolute velocity of the suspension. The outputs of the variable stiffness controller and the variable damping controller are both execution control forces.

[0059] In addition, the control algorithm of the controller can choose from a variety of control algorithms such as PID control algorithm, fuzzy control algorithm, adaptive control algorithm, sliding mode control algorithm or neural network control algorithm, and select and optimize according to the specific impact conditions; among them, the PID control algorithm has a simple structure, is easy to implement and debug, and is often used as the preferred control algorithm; the fuzzy control algorithm can handle some uncertainties and nonlinear problems, and is suitable for complex impact conditions; the adaptive control algorithm can automatically adjust the control parameters according to the real-time status of the system to improve the robustness and adaptability of the control system; the sliding mode control algorithm has the advantages of fast response speed and insensitivity to parameter changes and external interference, and is suitable for scenarios with high control accuracy requirements; in actual application, the advantages and disadvantages of various control algorithms can be comprehensively considered according to factors such as vehicle type, suspension system structure, and driving conditions, and the most appropriate control algorithm can be selected or multiple control algorithms can be used in combination to achieve the best suspension control effect.

[0060] In this embodiment, since the vehicle suspension system exhibits strong nonlinearity and uncertainty under impact conditions, and the fuzzy control algorithm does not require a precise mathematical model, it can effectively cope with the complex dynamic changes under impact conditions through fuzzy rules; therefore, the fuzzy control algorithm is used to control the variable stiffness controller and the variable damping controller; the variable stiffness controller is used to adjust the stiffness of the suspension, which is mainly related to the displacement and speed of the suspension, so the input of the variable stiffness controller is the relative displacement and relative speed of the suspension; the variable damping controller is used to adjust the damping of the suspension, which is mainly related to the suspension speed, so the input of the variable damping controller includes the relative speed and absolute speed of the suspension; by adopting the fuzzy control algorithm for the controller, flexible adjustment of the suspension stiffness and damping can be achieved to adapt to different impact conditions.

[0061] The design of a fuzzy controller includes three steps: fuzzification, fuzzy reasoning, and defuzzification. First, the input parameters of the suspension, such as relative displacement, relative velocity, and absolute velocity, are fuzzified and converted into fuzzy sets. Then, reasoning is performed according to preset fuzzy rules to obtain the fuzzy control output. Finally, the fuzzy control output is converted into precise execution control force through defuzzification. The fuzzy control algorithm can make full use of the nonlinear characteristics of the suspension system and improve the robustness and adaptability of the control system.

[0062] Further optionally, the fuzzy control algorithm needs to fuzzify the input signal, then perform fuzzy reasoning according to fuzzy rules, and finally defuzzify it to obtain the output control signal. This process takes a certain amount of time to complete, so the fuzzy control algorithm has a certain time lag. In this embodiment, the fuzzy control algorithm can also be combined with the adaptive control algorithm to design a fuzzy adaptive controller as a variable stiffness controller and a variable damping controller. The fuzzy adaptive controller can dynamically adjust the control parameters according to the real-time state of the suspension system to compensate for the time lag of the fuzzy control algorithm, thereby improving the response speed and stability of the control system. Specifically, other methods of reducing time lag can also be used to improve the response speed of the controller.

[0063] It should be noted that the above method of reducing response lag or delay is an optional step.

[0064] The implementation principle of Example 2 of the present application is: the variable stiffness controller and the variable damping controller are designed using a fuzzy control algorithm, which can enable the controller to respond quickly and accurately, and output the corresponding control force according to the real-time state of the vehicle, and dynamically adjust the stiffness and damping of the vehicle suspension system to cope with complex impact conditions and changes in vehicle state; and because the fuzzy control algorithm has a certain time lag, it is possible to design a fuzzy adaptive controller as a variable stiffness controller and a variable damping controller to reduce control delays, enhance system response speed and stability, further improve the adjustment accuracy and response speed of the suspension system, and bring passengers a more comfortable and stable riding experience.

[0065] Example 3: is substantially the same as Example 1, except that:

[0066] Reference Figure 3In the variable stiffness and variable damping control steps, it is necessary to determine the switching time for switching the variable stiffness control to the variable damping control; since the magnetorheological damper for variable damping control is a semi-active device, its control needs to follow the semi-active control conditions; when the relative speed and absolute speed of the suspension are reversed, variable damping control cannot be performed to reduce the body response acceleration, and variable stiffness control has a better control effect on the body response acceleration. When the relative speed and absolute speed of the suspension are not reversed, variable damping control can more effectively attenuate the body response acceleration and enable the system to reach a stable state faster; therefore, when the relative speed and absolute speed of the suspension are not reversed, the variable stiffness control is switched to the variable damping control; wherein the relative speed of the suspension is the speed of the sprung mass relative to the unsprung mass.

[0067] Furthermore, when the relative speed of the suspension equals zero for the first time, the variable stiffness control is switched to the variable damping control.

[0068] The implementation principle of Example 3 of the present application is: by analyzing the characteristics of the magnetorheological damper and following the semi-active control conditions, the time for switching the variable stiffness control to the variable damping control is set when the relative speed and the absolute speed of the suspension are not reversed, which can fully utilize the advantages of variable stiffness control and variable damping control, improve the attenuation effect of the response acceleration, and reduce vibration; further, the time for switching the variable stiffness control to the variable damping control is set when the relative speed of the suspension is equal to zero for the first time, that is, on the dividing line between the early and late stages of the impact excitation, which meets the semi-active control conditions of the magnetorheological damper, and the suspension system is in a relatively stable state at this time, which can avoid adjustments during the dynamic response process of the suspension system, reduce the dynamic response during the adjustment process, and help to better balance the vehicle's handling and comfort, and improve the comfort and stability of passengers.

[0069] Example 4: is substantially the same as Example 1, except that:

[0070] Reference Figure 4 A control exit step is provided after the variable stiffness and variable damping control step; by setting a response acceleration threshold, it is judged whether the vehicle is still in the impact condition; when the vehicle is in the impact condition, within a period of time, if the response acceleration is greater than or equal to the response acceleration threshold, it is determined that the vehicle is still in the impact condition, and the variable stiffness and variable damping control is continued; if the response acceleration is less than the response acceleration threshold, it is determined that the vehicle has exited the impact condition, and the variable damping control is terminated.

[0071] In this embodiment, the response acceleration threshold is set to 0.15 m / s². At this time, it can be considered as uniform speed driving, and the acceleration is close to zero. This acceleration is usually imperceptible to passengers and can provide a relatively smooth riding experience. Since the response acceleration is a fluctuating value in the impact condition, it is necessary to compare the response acceleration within a period of time with the response acceleration threshold. In this embodiment, the period of time is set to 3 seconds. The 3-second time window is a commonly used time range for evaluating the dynamic response of the vehicle under the impact condition. Within this time window, if the response acceleration is always less than the set response acceleration threshold, it can be considered that the vehicle has exited the impact condition.

[0072] In another specific implementation of this embodiment, in the step of obtaining real-time vehicle information, the road condition ahead in the direction of vehicle travel is also identified by a preview mechanism to obtain road condition data; and in the driving condition identification step, the road condition data is compared with the impact condition database to obtain the current working condition of the vehicle; a control exit step is provided after the variable stiffness and variable damping control step to determine whether the vehicle is still in an impact condition. When the vehicle is in an impact condition, if the road condition for a certain length ahead is not an impact condition, it is determined that the vehicle has exited the impact condition and the variable damping control is terminated; wherein, the identification of the road condition ahead in the direction of vehicle travel is performed using preview equipment such as laser radar and camera.

[0073] Specifically, a laser radar is used as a preview mechanism to identify road conditions. When the vehicle is in an impact condition, the preview mechanism is used to identify the road condition ahead in the direction of vehicle travel. If the road condition ahead is still an impact condition, variable stiffness and variable damping control is continued. If the road condition for a certain length ahead is not an impact condition, it is determined that the vehicle has exited the impact condition and the variable damping control is terminated.

[0074] The implementation principle of Example 4 of the present application is: by setting a response acceleration threshold, the response acceleration within a period of time is analyzed to determine whether the vehicle is still in an impact condition. When the vehicle has exited the impact condition, the variable stiffness and variable damping control is exited, effectively avoiding unnecessary control adjustments after the vehicle has stabilized or the impact condition has ended, thereby improving the control efficiency and stability of the suspension system; it is also possible to determine whether the vehicle is about to end the impact condition by obtaining the road condition data ahead in the direction of vehicle travel, and adjust the control method in advance to avoid switching after the impact condition has ended, causing control lag, which is beneficial to improving the response speed of the suspension system, so that the vehicle can maintain optimal handling and comfort under different conditions.

[0075] Example 5: is substantially the same as Example 2, except that:

[0076] Reference Figure 5In the step of obtaining real-time vehicle information, the road condition ahead of the vehicle in the driving direction is also identified by the preview mechanism to obtain road condition data; and in the driving condition identification step, the road condition data is compared with the impact condition database to obtain the current vehicle condition; if the road condition for a certain length ahead is an impact condition, it is determined that the vehicle is about to enter the impact condition, and variable stiffness control is performed in advance, which is beneficial to reducing response lag or delay; in this embodiment, the variable stiffness control is performed in advance by calculating the distance between the vehicle and the impact condition, and a distance threshold is set. When the current distance between the vehicle and the impact condition is greater than or equal to the set distance threshold, the variable stiffness control is switched; in other embodiments, it can also be determined with reference to the estimated arrival time.

[0077] Specifically, the distance between the vehicle and the impact condition is related to the vehicle's speed and the suspension system's response time. For example, assuming the vehicle is traveling at 80 km / h, the vehicle system takes 0.5 seconds to recognize the impact condition and issue a variable stiffness control signal, and the suspension system's response time is 0.1 seconds. The distance is:

[0078] , that is, based on the above conditions, the distance threshold is set to 13.33m.

[0079] It should be noted that the calculation of this distance is only an example. In actual application, it needs to be adjusted and optimized according to the specific vehicle performance, driving environment and suspension system characteristics.

[0080] It should be noted that the above method of reducing response lag or delay is an optional step.

[0081] The implementation principle of Example 5 of the present application is: by adopting a method of identifying the road conditions ahead of the vehicle's driving direction, variable stiffness control is performed in advance, thereby ensuring that the suspension system is in the best working state before the impact condition occurs, and can better absorb and disperse the impact energy. This method can effectively reduce the impact on the vehicle and passengers, and improve riding comfort and safety.

[0082] Example 6: Reference Figure 6 The present application provides a variable stiffness and variable damping switching control system for a magnetorheological-air suspension under impact conditions, which adopts the following technical solutions:

[0083] A variable stiffness and variable damping switching control system for a magnetorheological-air suspension under impact conditions, comprising:

[0084] Database: used to store different impact conditions and corresponding vehicle driving parameters; vehicle driving parameters can be obtained through sensors or historical data; impact conditions are divided into levels according to different vehicle response states, including mild, moderate, severe, extreme, etc.; the corresponding vehicle driving parameters generally include key information such as vehicle speed, acceleration, relative speed, relative displacement, etc.; vehicle driving parameters can be obtained through sensors installed on the suspension or historical data, and sensors include speed sensors, acceleration sensors, displacement sensors, etc.

[0085] Vehicle real-time information acquisition module: used to collect vehicle driving parameters in real time; vehicle driving parameters are acquired in real time through sensors; the acquired parameters generally include key information such as vehicle speed, acceleration, relative speed, relative displacement, etc., and the collected vehicle driving parameters are output to the driving condition identification module.

[0086] Driving condition identification module: The input end is connected to the output end and database of the vehicle real-time information acquisition module; it is used to monitor and analyze the real-time driving parameters of the vehicle, and compare it with the impact condition database to determine the current working condition of the vehicle; if the vehicle is in an impact condition, a signal is sent to the controller module to ensure that the vehicle can obtain the best suspension performance under different impact conditions.

[0087] Controller module: The input end is connected to the output end of the driving condition identification module; it is used to control the variable stiffness shock absorber and the variable damping shock absorber according to the preset control algorithm for different impact conditions;

[0088] Variable stiffness shock absorber: The input end is connected to the output end of the controller module, and is used to adjust the variable stiffness execution control force and adjust the stiffness of the suspension system; in the embodiment of the present application, the variable stiffness shock absorber is an air spring.

[0089] Variable damping shock absorber: The input end is connected to the output end of the controller module and is used to adjust the variable damping execution control force to control the damping of the suspension system. In the embodiment of the present application, the variable damping shock absorber is a magnetorheological damper.

[0090] Example 7: The present application also provides a magnetorheological-air suspension vehicle, which adopts the magnetorheological-air suspension system provided by the present application; the magnetorheological-air suspension vehicle in this embodiment integrates the magnetorheological-air suspension system in Example 6, and the vehicle's suspension system can quickly identify the current working conditions based on the driving parameters monitored in real time, and adopt a variable stiffness and variable damping switching control method to cope with impact conditions, so as to adapt to various complex road conditions, thereby improving the vehicle's dynamic response capability, and improving the vehicle's stability and ride comfort under impact conditions.

[0091] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A method for controlling the variable stiffness and variable damping switching of a vehicle intelligent suspension under impact conditions, characterized by: The following steps are involved: Build an impact condition database: including different impact conditions and corresponding vehicle driving parameters; Obtain real-time vehicle information: collect vehicle driving parameters in real time; Driving condition identification: By monitoring and analyzing the vehicle's real-time driving parameters and comparing them with the impact condition database, the vehicle's current operating condition is determined. If the vehicle is in an impact condition, variable stiffness and damping control is implemented. Variable stiffness and variable damping control: The vehicle is first subjected to variable stiffness control according to the impact working conditions. After a period of time, the vehicle is subjected to variable damping control according to the impact working conditions. The stiffness is changed by the air spring, and the damping is changed by the magnetorheological damper. In the variable stiffness and variable damping control steps, a fuzzy control algorithm is used to control the variable stiffness controller and the variable damping controller, wherein the input of the variable stiffness controller includes the relative displacement and relative speed of the suspension, the input of the variable damping controller includes the relative speed and absolute speed of the suspension, and the outputs of the variable stiffness controller and the variable damping controller are both execution control forces; In the variable stiffness and variable damping control step, when the relative speed of the suspension is not opposite to the absolute speed, the variable stiffness control is switched to the variable damping control; wherein the relative speed is the speed of the sprung mass relative to the unsprung mass; In the variable stiffness and variable damping control step, when the relative speed of the suspension is equal to zero for the first time, the variable stiffness control is switched to the variable damping control; A control exit step is provided after the variable stiffness and variable damping control steps; Control Exit: Set the response acceleration threshold. When the vehicle is in an impact condition, if the response acceleration is less than the response acceleration threshold within a period of time, the vehicle is deemed to have exited the impact condition and variable damping control ends. In the step of obtaining real-time vehicle information, the road condition ahead of the vehicle in the direction of travel is also identified to obtain road condition data; In the driving condition identification step, the road condition data is also compared with the impact condition database to obtain the current vehicle condition.

2. The vehicle intelligent suspension variable stiffness and variable damping switching control method under impact conditions according to claim 1 is characterized in that: A control exit step is provided after the variable stiffness and variable damping control steps; Control exit: When the vehicle is in an impact condition, if the road condition for a certain distance ahead is not an impact condition, it is determined that the vehicle has exited the impact condition and the variable damping control is terminated.

3. A magnetorheological-air suspension system, the system being applicable to the control method according to any one of claims 1 to 2, characterized in that: include: Database: used to store different impact conditions and corresponding vehicle driving parameters; Vehicle real-time information acquisition module: used to collect vehicle driving parameters in real time; Driving condition identification module: used to monitor and analyze the vehicle's real-time driving parameters and compare them with the impact condition database to determine the vehicle's current condition; if the vehicle is in an impact condition, a signal is sent to the controller module; Controller module: used to control the variable stiffness shock absorber and variable damping shock absorber according to the preset control algorithm for different impact conditions; Variable stiffness shock absorber: used to adjust the execution control force; Variable damping shock absorber: used to adjust the execution control force.

4. A vehicle, characterized in that: The vehicle adopts the magnetorheological-air suspension system described in claim 3.

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