A state feedback control method for a whole vehicle active suspension with electro-hydraulic actuators

Abstract

The application discloses a state feedback control method for a whole vehicle active suspension with an electro-hydraulic actuator, and belongs to the technical field of vehicle suspension system control, which comprises the following steps: acquiring road feature data, generating a vehicle inclination prediction angle; acquiring electro-hydraulic actuator state data and vehicle state data, generating a suspension target support force; acquiring the current support force of the electro-hydraulic actuator, generating a resistance adjustment demand value; generating a servo valve target flow of the electro-hydraulic actuator according to the resistance adjustment demand value; generating a servo valve control voltage of the electro-hydraulic actuator according to the servo valve target flow of the electro-hydraulic actuator, and controlling the suspension system of the vehicle; the vehicle inclination angle is predicted by acquiring the road feature data, the target support force model is established by combining the actuator and the vehicle state, and the servo valve control signal is generated based on the real-time support force deviation, so that the dynamic and accurate adjustment of the suspension system is realized, and the control ability, control precision and servo valve adjustment performance of the vehicle suspension system are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vehicle suspension system control, and particularly relates to a state feedback control method for a whole vehicle active suspension with an electro-hydraulic actuator. BACKGROUND

[0002] With the rapid development of the automotive industry, the stability, comfort and handling of vehicle driving have become the focus of consumers and manufacturers. As an important part of the vehicle, the suspension system plays a crucial role in these performances. The traditional passive suspension system, due to its fixed stiffness and damping characteristics, is difficult to adapt to complex and variable road conditions and vehicle driving states, thus limiting the further improvement of vehicle performance. Especially when facing complex road features, such as changes in road horizontal inclination, pit depth and width, the traditional suspension system cannot achieve dynamic adjustment, resulting in obvious bumps and tilts during vehicle driving, which seriously affects the ride comfort and handling stability.

[0003] Currently, active suspension systems mainly use electro-hydraulic actuators, motors or other power sources to adjust the stiffness and damping of the suspension system in real time to adapt to different road conditions and vehicle driving states. Among these systems, electro-hydraulic actuators are widely used due to their high power density and fast response speed. However, existing control methods for active suspension systems based on electro-hydraulic actuators mostly use open-loop control or simple closed-loop feedback control. Although these methods can improve the driving performance of the vehicle to some extent, they have obvious limitations. First, existing methods lack accurate prediction ability for road features, and cannot obtain key information such as road horizontal inclination, pit depth and width in advance, resulting in passive response of the suspension system to the road changes that have already occurred, and the inability to achieve forward-looking control. Second, existing control strategies often only consider a single factor, without considering multi-dimensional information such as road features, vehicle state and actuator state, resulting in insufficient control accuracy. In addition, existing servo valve control methods are not accurate enough in regulating flow and pressure, making it difficult to achieve fast and smooth force adjustment, affecting the overall response performance of the system. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a state feedback control method for a whole vehicle active suspension with an electro-hydraulic actuator, which solves the above problems.

[0005] To achieve the above purpose, the present application realizes the following technical scheme: a state feedback control method for a whole vehicle active suspension with an electro-hydraulic actuator, comprising the following steps:

[0006] Obtain road feature data and generate a vehicle tilt prediction angle;

[0007] Obtaining electro-hydraulic actuator state data and vehicle state data, establishing a suspension target pressure analysis model according to the vehicle inclination prediction angle, the electro-hydraulic actuator state data and the vehicle state data, and generating a suspension target support force;

[0008] Obtaining the current support force of the electro-hydraulic actuator, generating a resistance adjustment demand value according to the suspension target support force and the current support force of the electro-hydraulic actuator;

[0009] Generating a servo valve target flow of the electro-hydraulic actuator according to the resistance adjustment demand value;

[0010] Generating a servo valve control voltage of the electro-hydraulic actuator according to the servo valve target flow of the electro-hydraulic actuator;

[0011] Controlling the suspension system of the vehicle according to the servo valve control voltage of the electro-hydraulic actuator.

[0012] On the basis of the above technical scheme, the application further provides the following optional technical schemes:

[0013] Further technical scheme: the generation mode of the vehicle inclination prediction angle specifically includes:

[0014] Obtaining road surface feature data; wherein the road surface feature data includes a road surface horizontal inclination angle, a road surface pit depth and a road surface pit width;

[0015] Establishing an inclination angle prediction model according to the road surface horizontal inclination angle, the road surface pit depth and the road surface pit width, and generating the vehicle inclination prediction angle.

[0016] Further technical scheme: the inclination angle prediction model is:

[0017] ;

[0018] Wherein, represents the vehicle inclination prediction angle, θ t represents the road surface horizontal inclination angle, d t represents the road surface pit depth, W t represents the road surface pit width, V represents the current vehicle speed, and ω represents a unit conversion coefficient, represents the current vehicle inclination angle, K1 is a road surface inclination weight coefficient, K2 is a pit impact weight coefficient, and K3 is a dynamic response weight coefficient.

[0019] Further technical scheme: the expression of the suspension target pressure analysis model is specifically:

[0020] ;

[0021] Wherein, F targetThe suspension target support force is represented by m, the spring mass of the electro-hydraulic actuator is represented by n actuator The total number of vehicle electro-hydraulic actuators is represented by The vehicle inclination prediction angle is represented by a lat The vehicle lateral acceleration is represented by g, and the gravitational acceleration is represented by g.

[0022] Further technical solutions: the generation mode of the vehicle lateral acceleration is specifically:

[0023] Through the formula:

[0024] ;

[0025] The vehicle lateral acceleration a lat ;

[0026] In the formula, V represents the current vehicle speed, ω represents the unit conversion coefficient, and R represents the vehicle steering radius.

[0027] Further technical solutions: the generation mode of the resistance adjustment demand value is specifically:

[0028] Through the formula:

[0029] ;

[0030] The resistance adjustment demand value ΔF is generated.

[0031] In the formula, F sensor represents the current support force of the electro-hydraulic actuator.

[0032] Further technical solutions: the generation mode of the servo valve target flow of the electro-hydraulic actuator specifically includes:

[0033] According to the resistance adjustment demand value, the pressure adjustment value of the electro-hydraulic actuator is generated;

[0034] According to the pressure adjustment value of the electro-hydraulic actuator, a servo valve flow analysis model is established to generate the servo valve target flow of the electro-hydraulic actuator.

[0035] Further technical solutions: the generation mode of the pressure adjustment value of the electro-hydraulic actuator is specifically:

[0036] Through the formula:

[0037] ;

[0038] The pressure adjustment value ΔP of the electro-hydraulic actuator is generated.

[0039] In the formula, ΔF represents the resistance adjustment demand value, A prepresents the effective action area of the piston of the electro-hydraulic actuator.

[0040] Further technical solutions: the expression of the servo valve flow analysis model is specifically:

[0041] ;

[0042] Wherein, Q represents the target flow of the servo valve of the electro-hydraulic actuator, C d represents the flow efficiency coefficient of the valve port, A v represents the flow area of the servo valve opening, sgn (△F) represents the direction control function, which is used to determine the flow direction according to the positive and negative of △F, represents the density of hydraulic oil.

[0043] Further technical solutions: the generation mode of the servo valve control voltage of the electro-hydraulic actuator is specifically:

[0044] ;

[0045] Wherein, u k represents the servo valve control voltage of the electro-hydraulic actuator, △F represents the resistance adjustment demand value, △F k-1 represents the resistance adjustment demand value of the previous moment, △t represents the sampling period of the electro-hydraulic actuator control system, K p represents the response intensity of the control voltage to the force deviation, K d represents the response intensity of the control voltage to the force rate of change.

[0046] The present application provides a kind of state feedback control method of whole vehicle active suspension with electro-hydraulic actuator, compared with prior art has the following beneficial effects:

[0047] The present application predicts the vehicle inclination angle by acquiring road feature data, establishes a target support force model by combining the actuator and vehicle state, and generates a servo valve control signal based on real-time support force deviation, achieving dynamic and accurate adjustment of the suspension system, improving the control ability, control accuracy and optimizing the servo valve adjustment performance of the vehicle suspension system. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 A flowchart of the state feedback control method of whole vehicle active suspension with electro-hydraulic actuator provided by the embodiment of the present application.

[0049] Figure 2 A flowchart of S1 provided by the embodiment of the present application.

[0050] Figure 3 A flowchart of S4 provided by the embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0052] In the prior art, the control method of the vehicle suspension system relies on a real-time feedback mechanism, and the vehicle posture and road surface information are collected by sensors for lag adjustment. Due to the lack of prediction ability of road surface characteristics, when the vehicle encounters sudden road surface changes, the suspension system cannot predict the vehicle inclination trend in advance, resulting in that the adjustment action lags behind the actual demand. For example, in a continuous curve or a dense pothole section, the traditional method can only passively adjust the support force according to the current vehicle state, and cannot offset the vehicle body inclination that is about to occur, resulting in a decrease in vehicle stability and a sense of discomfort of the passengers.

[0053] In order to solve the above problems, the inventors found that the root cause of the response lag of the suspension system in the prior art lies in the lack of prediction modeling ability of road surface characteristics. By analyzing the vehicle driving dynamics characteristics, the inventors proposed to include parameters such as road surface horizontal inclination, pothole depth and width into the prediction model, and to establish an inclination angle prediction mechanism in combination with the real-time motion state of the vehicle. Further, the inventors realized that relying only on the prediction model is still insufficient to achieve precise control, and it is necessary to couple the prediction results with the mechanical parameters of the electro-hydraulic actuator and the characteristics of the hydraulic system for coupled analysis, forming a full-closed loop control link from prediction to execution.

[0054] The specific implementation of the present application is described in detail below in combination with specific examples.

[0055] Please refer to Figure 1 A state feedback control method of a whole vehicle active suspension with an electro-hydraulic actuator is provided for an embodiment of the present application, which comprises the following steps:

[0056] S1: acquiring road surface characteristic data to generate a vehicle inclination prediction angle;

[0057] S2: acquiring electro-hydraulic actuator state data and vehicle state data, establishing a suspension target pressure analysis model according to the vehicle inclination prediction angle, the electro-hydraulic actuator state data and the vehicle state data, and generating a suspension target support force;

[0058] S3: acquiring a current support force of the electro-hydraulic actuator, generating a resistance adjustment demand value according to the suspension target support force and the current support force of the electro-hydraulic actuator;

[0059] S4: generating a servo valve target flow of the electro-hydraulic actuator according to the resistance adjustment demand value;

[0060] S5: generating a servo valve control voltage of the electro-hydraulic actuator according to the servo valve target flow of the electro-hydraulic actuator;

[0061] S6: controlling the suspension system of the vehicle according to the servo valve control voltage of the electro-hydraulic actuator;

[0062] The road surface feature data refers to a multi-dimensional parameter set including a road surface horizontal inclination, a pothole depth and a width, and can be specifically realized by using a laser radar or a visual sensor in cooperation with a road surface scanning algorithm, and is used to represent the geometric features of the road section to be passed by the vehicle.

[0063] The vehicle inclination prediction angle refers to a future attitude angle of the vehicle calculated by an inclination angle prediction model, and is specifically realized by using a mathematical model fusing road surface features and vehicle dynamics parameters, and is used to predict the body inclination trend in advance.

[0064] The suspension target support force refers to a theoretical support force value required by the electro-hydraulic actuator, and is specifically converted into a mechanical parameter by a suspension target pressure analysis model, and is used to guide the output adjustment of the actuator.

[0065] The resistance adjustment demand value refers to a deviation amount of the target support force and the actual support force, and is specifically obtained by comparing and calculating real-time data, and is used to determine the adjustment direction and amplitude of the hydraulic system.

[0066] The servo valve target flow refers to the hydraulic oil flow required to realize pressure adjustment, and is specifically converted into a flow parameter from a pressure difference according to a fluid mechanics formula, and is used to control the opening degree of the servo valve.

[0067] The servo valve control voltage refers to an electric signal for driving the servo valve to act, and is specifically converted into a voltage instruction from the flow demand by a control algorithm, and is used to realize accurate adjustment of the hydraulic system.

[0068] Specifically, after the road surface feature data is acquired, it is input into the inclination angle prediction model, the influences of the road surface inclination, the pothole depth and the width on the vehicle attitude are calculated by weighted calculation, and the inclination prediction angle with time foresight is generated. The prediction angle and the real-time vehicle state parameter are jointly input into the suspension target pressure analysis model, and the support force required to offset the predicted inclination is calculated. By continuously monitoring the actual output force of the electro-hydraulic actuator, the system dynamically calculates the deviation between the current support force and the target value, and generates the resistance adjustment value representing the adjustment demand. The adjustment value is converted into the target flow parameter of the servo valve through the hydraulic system characteristic model, and finally the servo valve driving voltage is generated through the proportional-differential control algorithm, forming a full-closed loop control system from prediction to execution.

[0069] Compared with the prior art, the existing method only makes feedback adjustment based on the current vehicle state, while the present scheme realizes predictive control of the suspension system by establishing a road feature prediction model and a suspension target pressure analysis model; in the traditional technology, the control signal of the servo valve is directly derived from the vehicle attitude deviation, while in the present scheme, the mechanical deviation is converted into a hydraulic system parameter to construct a mechanical-hydraulic combined control link, thereby improving the response accuracy of the system.

[0070] Through the above technical scheme, the present application can predict in advance the tilting trend of the vehicle due to the road feature, complete support force adjustment before the vehicle body actually tilts, and effectively eliminate the control lag phenomenon; by establishing a dynamic mapping relationship between the predicted angle and the support force, the accurate matching of the actuator output and the vehicle motion state is ensured. The closed-loop feedback mechanism is used to continuously correct the control parameters, which significantly improves the body stability under complex road conditions and reduces the energy loss caused by adjustment lag.

[0071] Referring to Figure 2 , the present application further proposes a generation method of the vehicle tilting prediction angle, which specifically includes:

[0072] S1.1: acquiring road feature data; wherein the road feature data includes a road horizontal inclination angle, a road pit depth and a road pit width;

[0073] S1.2: establishing a tilting angle prediction model according to the road horizontal inclination angle, the road pit depth and the road pit width to generate a vehicle tilting prediction angle;

[0074] The road horizontal inclination angle refers to the lateral inclination angle of the road, which can be measured in real time by a vehicle-mounted gyroscope or a laser radar, and is used to represent the inclination degree of the road in the driving direction of the vehicle;

[0075] The road pit depth refers to the vertical height difference of the road concave area, which can be detected by an ultrasonic sensor or a visual recognition system, and is used to quantify the impact strength of the road unevenness on the vehicle body;

[0076] The road pit width refers to the lateral extension size of the road concave area, which can be scanned and measured by a binocular camera or a millimeter wave radar, and is used to reflect the dynamic response time window when the vehicle passes through the pit area;

[0077] The tilting angle prediction model refers to a mathematical calculation model that fuses multi-dimensional road feature parameters, which can be constructed by using a linear weighting or a nonlinear regression algorithm, and realizes the prediction of the vehicle tilting trend by dynamically adjusting the weight coefficients of the parameters;

[0078] Specifically, by simultaneously collecting three types of characteristic parameters of road surface horizontal inclination, pothole depth and pothole width, a multi-dimensional road surface feature representation system is established; the road surface horizontal inclination is taken as the basic inclination component, and a preset weight coefficient is used to reflect the direct influence degree of the inclination component on the vehicle inclination; the pothole depth data is processed by standardization and multiplied by a dynamic response weight coefficient to represent the instantaneous impact strength of different depth depressions on the suspension system; the pothole width parameter is dynamically associated with the current vehicle speed, and the response sensitivity of the prediction model is dynamically adjusted by introducing the ratio of the vehicle speed to the pothole width; and the current vehicle inclination angle is introduced as a feedback correction term to compensate for the prediction error through a real-time feedback mechanism, so as to ensure the dynamic matching of the prediction result and the actual driving state.

[0079] The application further proposes the inclination angle prediction model, in particular:

[0080] ;

[0081] Among them, represents the vehicle inclination prediction angle, θ t represents the road surface horizontal inclination, d t represents the road surface pothole depth, W t represents the road surface pothole width, V represents the current vehicle speed, and ω represents the unit conversion coefficient. represents the current vehicle inclination angle, K1 is the road surface inclination weight coefficient, K2 is the pothole impact weight coefficient, and K3 is the dynamic response weight coefficient.

[0082] Among them, the road surface horizontal inclination θ t is the angle between the vehicle driving direction and the horizontal plane, which can be collected by an inertial measurement unit or a laser radar, and is used to reflect the static inclination characteristics of the road surface.

[0083] The road surface pothole depth d t is the vertical height of the pothole area, which can be measured by a three-dimensional vision sensor or an ultrasonic sensor, and is used to quantify the impact strength of the pothole on the vehicle attitude.

[0084] The road surface pothole width W t is the horizontal span of the pothole along the vehicle driving direction, which can be obtained by image processing technology or laser ranging device, and is used to represent the spatial distribution characteristics of the pothole.

[0085] The current vehicle inclination angle is the real-time attitude angle of the vehicle, which can be calculated by a gyroscope or a suspension displacement sensor, and is used to dynamically correct the prediction result.

[0086] The dynamic response weight coefficient K3 is the ratio of the vehicle speed V to the pothole width W tThe adjustment parameter of the coupling term, which can be determined through experiment calibration or optimization algorithm, is used to balance the influence degree of vehicle motion state on prediction;

[0087] The unit conversion coefficient ω is a dimensionless parameter, which can be set based on the International System of Units, and is used to eliminate the interference of the dimension difference of different physical quantities on model operation;

[0088] The application further proposes an expression of the suspension target pressure analysis model, specifically:

[0089] ;

[0090] Where F target represents the suspension target support force, m represents the sprung mass of the electro-hydraulic actuator, n actuator represents the total number of vehicle electro-hydraulic actuators, represents the vehicle tilt prediction angle, a lat represents the vehicle lateral acceleration, and g represents the gravitational acceleration;

[0091] Where the sprung mass m of the electro-hydraulic actuator refers to the vehicle mass supported by the suspension system, which can be obtained in real time by using a vehicle body mass sensor or a sprung mass estimation algorithm, and is used to reflect the basic demand of vehicle static load on support force;

[0092] The total number n of vehicle electro-hydraulic actuators actuator refers to the number of actuators installed on the vehicle chassis, which is determined by vehicle design parameters, and is used to distribute the total support force to each actuator;

[0093] The vehicle tilt prediction angle refers to the future tilt angle of the vehicle generated by the road feature prediction model, which can be realized by an inertial measurement unit or a visual sensor combined with a prediction algorithm, and is used to quantify the influence of road inclination on support force in advance;

[0094] The vehicle lateral acceleration a lat refers to the acceleration generated when the vehicle is turning or moving laterally, which can be calculated by an acceleration sensor or a dynamic model based on vehicle speed and steering radius, and is used to represent the additional demand of centrifugal force on support force in dynamic driving;

[0095] The gravitational acceleration g is a physical constant, which is used to convert mass into gravitational component.

[0096] Specifically, the technical scheme reflects the influence of the static load of the vehicle on the support force by taking the product of the sprung mass and the gravitational acceleration as a basic term; reflects the dynamic demand of the road inclination on the support force by converting the inclination prediction angle into a vertical component force through a sine function; reflects the additional effect of the centrifugal force on the support force when the vehicle is turning by superimposing the product of the lateral acceleration and the sprung mass; and finally realizes the balanced distribution of the support force of each actuator by dividing the total support force by the number of actuators. During the driving process of the vehicle, when the road inclination or the lateral acceleration changes are detected, the model calculates the target support force in real time, so that the electro-hydraulic actuator adjusts the output force in advance to offset the lateral force generated by the road inclination or turning, thereby maintaining the stability of the vehicle body.

[0097] The application further proposes a generation method of the vehicle lateral acceleration, specifically:

[0098] The vehicle lateral acceleration a is generated by the formula:

[0099] ;

[0100] The vehicle lateral acceleration a is generated by the formula: lat ;

[0101] In the formula, V represents the current vehicle speed, ω represents the unit conversion coefficient, and R represents the vehicle turning radius.

[0102] The current vehicle speed V refers to the instantaneous speed of the vehicle driving, which can be collected in real time by a speed sensor and converted into an electrical signal for processing. Its function is to provide a speed parameter for lateral acceleration calculation.

[0103] The unit conversion coefficient ω is a proportionality factor for unifying the physical dimension, which can be converted by a preset numerical parameter. Its function is to eliminate the calculation error caused by different unit systems.

[0104] The vehicle turning radius R refers to the curvature radius of the trajectory when the vehicle is turning, which can be calculated by a steering wheel angle sensor combined with the wheelbase parameter of the vehicle. Its function is to reflect the geometric characteristics of the centrifugal force in the turning process.

[0105] Specifically, the formula establishes a mathematical model of lateral acceleration by the ratio of the square of the vehicle speed to the steering radius. The square of the vehicle speed reflects the nonlinear relationship between the centrifugal force and the speed, the steering radius parameter reflects the influence of the turning trajectory on the lateral acceleration, and the unit conversion coefficient is used to adjust the dimensional consistency. When the vehicle is turning, the system obtains the vehicle speed and steering radius data in real time, substitutes them into the formula to calculate the lateral acceleration, and further provides dynamic input for the analysis of the target support force of the suspension. By taking the vehicle speed and steering radius as the core variables, the kinematic characteristics of the vehicle can be directly related to the change of the lateral force, avoiding the delay problem caused by relying on sensor measurement, and realizing real-time prediction of the lateral acceleration under the steering condition.

[0106] The application further proposes a generation method of the resistance adjustment demand value, specifically:

[0107] The resistance adjustment demand value ΔF is generated by the formula:

[0108] ;

[0109]

[0110] In the formula, F sensor represents the current support force of the electro-hydraulic actuator;

[0111] wherein the resistance adjustment demand value ΔF is the dynamic difference between the target support force and the current support force, which can be realized by using a pressure sensor to collect the hydraulic cylinder pressure of the electro-hydraulic actuator in real time and converting it into a support force. The difference is used to quantify the deviation between the actual output of the suspension system and the ideal state;

[0112] wherein the target support force F target is the theoretical support force provided by the suspension system to cope with the predicted road conditions, which can be calculated by combining the suspension target pressure analysis model, the vehicle inclination prediction angle, the sprung mass and the lateral acceleration. This parameter reflects the comprehensive prediction result of the system for multi-dimensional driving conditions;

[0113] wherein the current support force F sensor is the actual output support force of the electro-hydraulic actuator under real-time conditions, which can be directly measured by using a strain gauge force sensor or a hydraulic pressure sensor. This parameter provides feedback input of the actual working condition for closed-loop control.

[0114] Specifically, during vehicle driving, the suspension target support force F target is generated by model calculation based on the vehicle inclination prediction angle, the sprung mass and the lateral acceleration, and the current support force F sensor； ​The difference between the two is ΔF, which directly represents the force deviation that the suspension system needs to compensate; for example, when the vehicle passes through a bumpy road, the target support force will increase in advance according to the prediction model, while the current support force may be lower than the target value due to the response delay of the actuator, at which time ΔF will generate a positive value signal to drive the servo valve to increase the flow output. This closed-loop calculation method based on the measured value and the target value can eliminate the cumulative deviation caused by model prediction error or external disturbance in traditional open-loop control, ensuring that the support force adjustment instruction is always synchronized with the actual demand.

[0115] Referring to Figure 3 The application further proposes a generation method of the servo valve target flow of the electro-hydraulic actuator, specifically including the following steps:

[0116] S4.1: generating a pressure adjustment value of the electro-hydraulic actuator according to the resistance adjustment demand value;

[0117] S4.2: establishing a servo valve flow analysis model according to the pressure adjustment value of the electro-hydraulic actuator to generate a servo valve target flow of the electro-hydraulic actuator;

[0118] The resistance adjustment demand value refers to the deviation between the target support force and the actual support force, which can be calculated by subtracting the current support force measured by the sensor from the suspension target support force, and is used to represent the force difference that needs to be compensated by the suspension system;

[0119] The pressure adjustment value refers to the conversion of the force deviation into the pressure change of the hydraulic system, which can be obtained by dividing the resistance adjustment demand value by the effective piston action area, and this parameter converts mechanical force control into hydraulic pressure control;

[0120] The servo valve flow analysis model refers to a flow calculation equation established based on the principle of fluid mechanics, which can be constructed by using the valve port flow efficiency coefficient, the flow area, the hydraulic oil density, and the pressure square root relationship, and is used to convert the pressure adjustment value into the control signal of the servo valve opening area and the oil flow direction.

[0121] Specifically, this technical solution first converts the resistance adjustment demand value into the pressure adjustment value through the effective piston action area, so that the force control target is converted into the pressure control target of the hydraulic system; then, based on the servo valve flow analysis model, combined with the hydraulic oil density, the valve port flow efficiency coefficient and other parameters, the oil flow direction is determined by the direction control function, and the target flow corresponding to the servo valve opening area is dynamically calculated according to the pressure adjustment value; this process realizes the closed-loop mapping from force deviation to hydraulic flow control through the direct association of physical parameters, ensuring that the suspension system can quickly adjust the support force according to the real-time road conditions.

[0122] The application further proposes that the generation method of the pressure adjustment value of the electro-hydraulic actuator is specifically:

[0123] By formula:

[0124] ;

[0125] The pressure adjustment value ΔP of the electro-hydraulic actuator is generated;

[0126] In the formula, ΔF represents the resistance adjustment demand value, A p represents the effective piston action area of the electro-hydraulic actuator;

[0127] Among them, the resistance adjustment demand value ΔF refers to the difference between the target support force and the actual support force, which can be realized by measuring the actuator output force in real time through a pressure sensor and calculating the deviation from the target value. This parameter directly reflects the dynamic adjustment amount required by the suspension system.

[0128] The effective piston action area A p refers to the effective projection area of the actuator piston pressure surface, which can be obtained by measuring the piston diameter or consulting the actuator technical parameter manual. This parameter, as a structural constant, participates in pressure conversion calculation to ensure that the force-pressure conversion relationship is strictly matched with the mechanical structure of the actuator.

[0129] Specifically, this technical solution performs ratio operation on the resistance adjustment demand value ΔF and the effective piston action area A p , and converts the force adjustment amount required by the suspension system into the pressure adjustment amount of the hydraulic system.

[0130] When the control system calculates the deviation between the target support force and the current support force, it directly uses the formula ΔP=ΔF / A p to perform algebraic operation, without relying on empirical coefficients or complex table lookup process, thereby eliminating the conversion error caused by the difference in actuator models in the traditional method.

[0131] The effective piston action area as an inherent structural parameter participates in the calculation, so that the pressure adjustment amount can automatically adapt to the mechanical characteristics of different specifications of actuators. For example, when a large-diameter piston is used, the pressure adjustment amount corresponding to the same force deviation will decrease in inverse proportion to the area. This physical dimension matching mechanism ensures the physical rationality of the pressure control command.

[0132] The expression of the servo valve flow analysis model is specifically:

[0133] ;

[0134] Among them, Q represents the target flow of the electro-hydraulic actuator servo valve, C d represents the valve port flow efficiency coefficient, and A vrepresents the flow area of the servo valve opening, and sgn(△F) represents a direction control function for determining the flow direction according to the positive and negative of △F, represents the density of the hydraulic oil;

[0135] wherein C d represents the flow efficiency coefficient of the valve port, which can be determined by experiment calibration or theoretical calculation, and is used for correcting the deviation between the actual flow and the theoretical flow to ensure the accuracy of the flow calculation;

[0136] represents the flow area of the servo valve opening, v represents the effective flow area of the servo valve opening, which can be adjusted by adjusting the displacement of the valve core or the opening ratio, and is used for directly correlating the flow and the mechanical structure parameters of the valve;

[0137] The direction control function sgn(△F) is used for automatically switching the inflow or outflow direction of the hydraulic oil according to the positive and negative of the resistance adjustment demand value △F, and can be realized by using a sign function.

[0138] represents the density of the hydraulic oil, represents the mass density of the hydraulic oil, which can be obtained by real-time measurement by a sensor or a preset calibration value, and is used for correlating the physical characteristic parameters of the pressure difference and the flow.

[0139] Specifically, the servo valve flow analysis model dynamically corrects the nonlinear relationship between the pressure difference and the flow by combining the pressure adjustment value △P and the density of the hydraulic oil , so as to avoid the flow control deviation caused by the change of the oil density;

[0140] The direction control function sgn(△F) automatically determines the flow direction of the servo valve according to the positive and negative of the resistance adjustment demand value △F, without the need of additional judgment of the pressure adjustment direction, thereby simplifying the control logic. The introduction of the flow efficiency coefficient C d of the valve port and the flow area A v makes the model be able to reflect the energy loss and the mechanical structure limitation of the actual hydraulic system, thereby ensuring the physical rationality and the engineering applicability of the target flow calculation;

[0141] In some specific embodiments, the value of the flow efficiency coefficient C d of the valve port can be 0.6 to 0.8, for example, obtained by experiment calibration; the flow area A v of the servo valve opening can be a parameter that varies linearly according to the displacement of the valve core, for example, adjusted by real-time feedback of a displacement sensor; and the value of the density of the hydraulic oil can be 850 kg / m³ to 900 kg / m³, for example, compensated and corrected by a temperature sensor.

[0142] The application further proposes a generation mode of the servo valve control voltage of the electro-hydraulic actuator, specifically:

[0143] ;

[0144] Wherein, u k represents the servo valve control voltage of the electro-hydraulic actuator, △F represents the resistance adjustment demand value, △F k-1 represents the resistance adjustment demand value at the last moment, △t represents the sampling period of the electro-hydraulic actuator control system, K p represents the response intensity of the control voltage to the force deviation, K d represents the response intensity of the control voltage to the force change rate.

[0145] Wherein, the resistance adjustment demand value △F refers to the difference between the target support force and the current support force, which can be specifically realized by measuring the hydraulic cylinder pressure of the electro-hydraulic actuator in real time through the pressure sensor and converting it into a force value, and is used to reflect the dynamic adjustment amount required by the suspension system.

[0146] The resistance adjustment demand value △F k-1 at the last moment refers to the adjustment demand value recorded by the control system at the last sampling period, which can be specifically realized by buffering the historical data through the storage module, and is used to calculate the force change trend.

[0147] The sampling period △t refers to the time interval of data collection and operation of the control system, which can be specifically realized by triggering data update through a clock signal with fixed frequency, and is used to ensure the stability of the control timing.

[0148] The response intensity K p of the control voltage to the force deviation and the response intensity K d of the control voltage to the force change rate refer to the weight parameters of the proportional term and the differential term in the control voltage, which can be specifically determined through experimental calibration or simulation optimization, and are used to adjust the sensitivity of the control voltage to the force deviation and the change rate.

[0149] Specifically, the generation of the servo valve control voltage is divided into two parts: the proportional term directly generates a basic control quantity according to the deviation between the current resistance adjustment demand value and the target value, realizing fast compensation of force deviation; the differential term generates a predictive control quantity by calculating the change rate of the resistance adjustment demand value in the adjacent sampling period, suppressing force fluctuations caused by road impact or vehicle body inertia. The setting of the sampling period makes the control process discrete, adapting to the operation characteristics of the digital controller. Independent adjustment of the response intensity coefficient allows the response characteristics of the control voltage to static deviation and dynamic disturbance to be optimized separately for different suspension characteristics of different vehicle models or different driving conditions; for example, the weight coefficient of the differential term can be increased when driving on bumpy roads to suppress high-frequency vibrations in advance; the weight coefficient of the proportional term can be increased when driving on flat roads to improve steady-state control accuracy.

[0150] While embodiments of the present application have been shown and described, it is to be understood that the embodiments described are merely divergences, modifications, replacements and variations of the embodiments of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A state feedback control method for a vehicle's active suspension with an electro-hydraulic actuator, characterized in that, Includes the following steps: Acquire road surface feature data and generate vehicle tilt prediction angle; Acquire electro-hydraulic actuator status data and vehicle status data, and establish a suspension target pressure analysis model based on the vehicle tilt prediction angle, electro-hydraulic actuator status data and vehicle status data to generate suspension target support force; The specific expression for the suspended target pressure analysis model is as follows: ; Among them, F target This represents the supporting force of the suspended target, m represents the sprung mass of the electro-hydraulic actuator, and n... actuator This indicates the total number of electro-hydraulic actuators in the vehicle, ϕ pred This represents the predicted vehicle tilt angle, a. lat This represents the vehicle's lateral acceleration, and g represents the acceleration due to gravity. Obtain the current support force of the electro-hydraulic actuator, and generate the resistance adjustment requirement value based on the target support force of the suspension and the current support force of the electro-hydraulic actuator; Based on the resistance adjustment demand value, the target flow rate of the servo valve of the electro-hydraulic actuator is generated; Based on the target flow rate of the servo valve of the electro-hydraulic actuator, generate the servo valve control voltage of the electro-hydraulic actuator; The vehicle's suspension system is controlled by the servo valve control voltage of the electro-hydraulic actuator.

2. The state feedback control method for a vehicle active suspension with an electro-hydraulic actuator according to claim 1, characterized in that, The method for generating the vehicle tilt prediction angle specifically includes: S1.1: Obtain road surface feature data; whereby the road surface feature data includes the road surface horizontal slope angle, road surface pothole depth, and road surface pothole width; S1.2: Establish a tilt angle prediction model based on the road surface horizontal inclination angle, road surface pothole depth, and road surface pothole width to generate the vehicle tilt prediction angle.

3. The state feedback control method for a vehicle active suspension with an electro-hydraulic actuator according to claim 2, characterized in that, The tilt angle prediction model is as follows: ； Among them, ϕ pred This represents the predicted vehicle tilt angle, θ. t This represents the horizontal slope angle of the road surface, d t This indicates the depth of potholes on the road surface, W. t This represents the width of the pothole, V represents the current vehicle speed, ω represents the unit conversion factor, and ϕ current This indicates the current vehicle tilt angle. K1 is the road surface tilt angle weighting coefficient, K2 is the pothole impact weighting coefficient, and K3 is the dynamic response weighting coefficient.

4. The state feedback control method for a vehicle active suspension with an electro-hydraulic actuator according to claim 1, characterized in that, The method for generating the vehicle's lateral acceleration is as follows: Through the formula: ； Generate the vehicle's lateral acceleration a lat ; In the formula, V represents the current vehicle speed, ω represents the unit conversion factor, and R represents the vehicle's turning radius.

5. The state feedback control method for a vehicle active suspension with an electro-hydraulic actuator according to claim 1, characterized in that, The specific method for generating the resistance adjustment demand value is as follows: Through the formula: ； Generate resistance adjustment demand value △F; In the formula, Fsensor represents the current supporting force of the electro-hydraulic actuator.

6. The state feedback control method for a vehicle active suspension with an electro-hydraulic actuator according to claim 1, characterized in that, The specific methods for generating the target flow rate of the servo valve in the electro-hydraulic actuator include: Based on the resistance adjustment demand value, the pressure adjustment value of the electro-hydraulic actuator is generated; A servo valve flow analysis model is established based on the pressure adjustment value of the electro-hydraulic actuator to generate the target flow rate of the servo valve for the electro-hydraulic actuator.

7. The state feedback control method for a vehicle active suspension with an electro-hydraulic actuator according to claim 6, characterized in that, The specific method for generating the pressure adjustment value of the electro-hydraulic actuator is as follows: Through the formula: ； Generate the pressure adjustment value ΔP of the electro-hydraulic actuator; In the formula, △F represents the resistance adjustment demand value, and A p This indicates the effective working area of ​​the piston in an electro-hydraulic actuator.

8. The state feedback control method for a vehicle active suspension with an electro-hydraulic actuator according to claim 6, characterized in that, The specific expression for the servo valve flow analysis model is as follows: ； Where Q represents the target flow rate of the servo valve in the electro-hydraulic actuator, and C... d This represents the valve orifice flow efficiency coefficient, A. v represents the flow cross-sectional area of ​​the servo valve opening, sgn(ΔF) represents the direction control function, used to determine the flow direction based on the sign of ΔF, and ρ represents the hydraulic oil density.

9. The state feedback control method for a vehicle active suspension with an electro-hydraulic actuator according to claim 1, characterized in that, The specific method for generating the servo valve control voltage of the electro-hydraulic actuator is as follows: ； Among them, u k This represents the servo valve control voltage of the electro-hydraulic actuator, and ΔF represents the resistance adjustment requirement value. k-1 This represents the resistance adjustment demand value at the previous moment, Δt represents the sampling period of the electro-hydraulic actuator control system, and K... p K represents the intensity of the control voltage's response to force deviation. d This represents the intensity of the control voltage's response to the rate of change of force.

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