CN118238564A - Air suspension vehicle height control method - Google Patents

Air suspension vehicle height control method Download PDF

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Publication number
CN118238564A
CN118238564A CN202410387634.0A CN202410387634A CN118238564A CN 118238564 A CN118238564 A CN 118238564A CN 202410387634 A CN202410387634 A CN 202410387634A CN 118238564 A CN118238564 A CN 118238564A
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China
Prior art keywords
vehicle body
control
vehicle
dead zone
height
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CN202410387634.0A
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Chinese (zh)
Inventor
郭中阳
丁仁凯
汪若尘
蒋业晖
孟祥鹏
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Jiangsu University
Jiangsu Chaoli Electric Inc
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Jiangsu University
Jiangsu Chaoli Electric Inc
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Priority to CN202410387634.0A priority Critical patent/CN118238564A/en
Publication of CN118238564A publication Critical patent/CN118238564A/en
Pending legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
    • B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
    • B60G2202/10—Type of spring
    • B60G2202/15—Fluid spring
    • B60G2202/152—Pneumatic spring
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/10—Acceleration; Deceleration
    • B60G2400/102—Acceleration; Deceleration vertical
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/25—Stroke; Height; Displacement
    • B60G2400/252—Stroke; Height; Displacement vertical
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2500/00—Indexing codes relating to the regulated action or device
    • B60G2500/20—Spring action or springs
    • B60G2500/201—Air spring system type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2500/00—Indexing codes relating to the regulated action or device
    • B60G2500/20—Spring action or springs
    • B60G2500/202—Height or leveling valve for air-springs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2500/00—Indexing codes relating to the regulated action or device
    • B60G2500/30—Height or ground clearance
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
    • B60G2800/90—System Controller type
    • B60G2800/91—Suspension Control
    • B60G2800/914—Height Control System

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Vehicle Body Suspensions (AREA)

Abstract

本发明公开了一种空气悬架车身高度控制方法，1、获取当前时刻车辆行驶状态参数；2、确定理想控制目标和双控制死区的大小；3、根据偏差大小判断是否超出大控制死区：若超出进入步骤4；若未超出进入步骤7；4、建立预测模型；5、求解理想的悬架系统输入量；6、根据理想的悬架系统输入量并基于小控制死区进行选择性反馈校正：若偏差小于小控制死区则进入步骤7；若偏差仍大于小控制死区则返回步骤4；7、判断是否存在偏差在小控制死区内振荡过大的极端现象，若存在则进入步骤8，若不存在则直接进入步骤9；8、输出模型预测补偿控制信号；9、进行保压控制，进行车身高度控制。减少了车身高度的振荡现象，提高了行驶安全性。

The invention discloses a method for controlling the height of an air suspension vehicle body, comprising the following steps: 1. obtaining vehicle driving state parameters at the current moment; 2. determining the ideal control target and the size of the double control dead zone; 3. judging whether the large control dead zone is exceeded according to the size of the deviation: if exceeded, entering step 4; if not exceeded, entering step 7; 4. establishing a prediction model; 5. solving the ideal suspension system input; 6. performing selective feedback correction based on the ideal suspension system input and the small control dead zone: if the deviation is less than the small control dead zone, entering step 7; if the deviation is still greater than the small control dead zone, returning to step 4; 7. judging whether there is an extreme phenomenon that the deviation oscillates too much in the small control dead zone, if so, entering step 8, and if not, directly entering step 9; 8. outputting a model prediction compensation control signal; 9. performing pressure holding control and vehicle body height control. The oscillation phenomenon of the vehicle body height is reduced, and driving safety is improved.

Description

Height control method for air suspension vehicle body
Technical Field
The invention relates to a vehicle height control method of an air suspension.
Background
With the rapid development of the automobile industry technology, the requirements on the riding comfort and the driving safety of the automobile are higher and higher, and the suspension system is one of the most important chassis components of the automobile, and the suspension system mainly has the function of transmitting the force and moment acting between wheels and a frame, so that the impact force generated when the automobile passes over an uneven road surface is relieved, and the caused vibration is reduced.
The traditional electric control air suspension is based on the adjustment of the height of the vehicle and the rigidity of the air spring at different vehicle speeds to improve the driving comfort and the system stability, but because the air suspension has stronger hysteresis and nonlinearity in the height adjustment process of the vehicle, the air spring is easy to generate the phenomenon of overcharge and overdischarge, so that the height of the vehicle can oscillate repeatedly near the target value. When carrying out real-time automobile body height closed-loop control, in order to stabilize automobile body height, the solenoid valve can switch control repeatedly, seriously influences solenoid valve life, has aggravated the oscillation phenomenon, has reduced system stability, has also influenced the travelling comfort of taking simultaneously.
Disclosure of Invention
In order to solve the problems, the invention provides the air suspension vehicle height control method, which solves the problems that the vehicle height repeatedly oscillates near the target value and the electromagnetic valve is frequently operated when the air suspension control scheme is used for closed-loop control, prolongs the service life of the electromagnetic valve, reduces the oscillation phenomenon of the vehicle height and improves the driving safety.
In order to achieve the technical purpose and the technical effect, the invention is realized by the following technical scheme:
the air suspension vehicle height control method comprises the following steps:
step 1, acquiring a vehicle running state parameter at the current moment;
step 2, determining the ideal control target and the sizes of double control dead zones delta 1 and delta 2 according to the running state parameters of the vehicle at the current moment;
And 3, determining the deviation between the actual vehicle body height and the target vehicle body height according to the vehicle body height signal, and judging whether the large control dead zone delta 2 is exceeded or not: if the large control dead zone delta 2 is exceeded, the step 4 is entered; if the large control dead zone delta 2 is not exceeded, the step 7 is entered;
Step 4, discrete linearization of the air suspension model and establishment of a prediction model;
Step 5, predicting the vehicle running state parameters of the corresponding time of N p time units in the future through a prediction model according to the vehicle running state parameters at the current time; establishing a prediction matrix according to the predicted vehicle running state parameters so as to optimally solve the ideal suspension system input quantity;
Step 6, performing selective feedback correction according to the ideal suspension system input quantity and based on the small control dead zone delta 1: outputting control signals of all electromagnetic valves according to the ideal input quantity of the suspension system, and entering a step 7 if the deviation between the actual vehicle body height and the target vehicle body height is smaller than a small control dead zone delta 1; if the deviation is still greater than the small control dead zone delta 1, returning to the step 4, feeding back the latest input condition, updating the vehicle running state parameters of the control system, updating the prediction model, and performing prediction analysis calculation and control after correction;
Step 7, judging whether an extreme phenomenon that the deviation oscillates too much in a small control dead zone delta 1 exists or not according to the deviation of the actual vehicle body height and the target vehicle body height and the change frequency, if so, entering the step 8, and if not, directly entering the step 9;
Step 8, outputting a model predictive compensation control signal;
and 9, performing pressure maintaining control, and outputting a normally closed PWM electromagnetic valve control signal of the electromagnetic valve to perform vehicle body height control.
Preferably, in step 1, the current time vehicle running state parameters include a current time vehicle speed, vehicle body heights at four wheels, air bag pressures of four air springs at each suspension, vehicle body vertical acceleration, vehicle body roll angle acceleration and vehicle body pitch angle acceleration.
Preferably, in step 2, the desired control targets include a target body height, a desired body vertical acceleration, a desired body roll angle, and a desired body pitch angle.
Preferably, in step2, the calculation formulas of the double control dead zones Δ 1 and Δ 2 are as follows:
Wherein v is the current vehicle speed, h d is the current target vehicle height, a, b, m and n are the small control dead zone vehicle speed gain coefficient, the small control dead zone target vehicle body height gain coefficient, the large control dead zone vehicle speed gain coefficient and the large control dead zone target vehicle body height gain coefficient, and c 1,c2 is the small control dead zone compensation factor and the large control dead zone compensation factor, respectively.
Preferably, in step 4, the prediction model is:
x(k+1)＝Ax(k)+Bu(k)
y(k)＝Cx(k)
Wherein x (k) is a suspension system state parameter at the current moment, including the vehicle body height at four wheels, the air pressure of four air spring air bags, the vehicle body roll angle acceleration and the vehicle body pitch angle acceleration, x (k+1) is a predicted suspension system state parameter of one time unit in the future, u (k) is a suspension system input quantity at the current moment, y (k) is a control target at the current moment, including the vehicle body height, the vehicle body vertical acceleration, the vehicle body roll angle and the vehicle body pitch angle, and A, B and C are coefficient matrixes determined by vehicle attributes.
Preferably, in step 5, a prediction matrix is established according to predicted values of vehicle running state parameters at corresponding moments of N p time units in the future:
wherein Y (k) is a predictive control target matrix of Y (k), U is a predictive system input matrix of U (k), And Θ is a coefficient matrix consisting of A, B, C;
By establishing evaluation indexes and optimizing and solving ideal suspension system input quantity according to a prediction matrix:
Wherein J is an evaluation index, Q is a weight matrix for expressing weight distribution of vehicle object states including vehicle body height, vehicle body vertical acceleration, vehicle body roll angle and vehicle body pitch angle, R is a weight matrix for expressing weight distribution of an inflation electromagnetic valve, a deflation electromagnetic valve and four switch electromagnetic valves for control input, N p is a prediction time, Y ref (k) is an ideal control target at the current moment, Y ref (k) is an ideal control target for predicting future conditions, Is the sum of the products of the squares of the elements of the matrix and the weights corresponding to the weight matrix Q,The sum of products of the weights corresponding to the square weight matrix R of each element of the matrix is taken as the corresponding u (k) when J takes the minimum value, and the input quantity of the suspension system is ideal.
Preferably, in step 8, the output model predictive compensation control is performed by taking the influence of hysteresis and time lag into consideration in step 4-5, determining the ratio from the double control dead zones Δ 1 and Δ 2, and outputting the output value of the original predictive control in proportion.
The beneficial effects of the invention are as follows:
According to the invention, the reasonable double dead zone control function is used for limiting the double control dead zone and combining with the model prediction algorithm, so that the control of the height of the vehicle body is realized, on one hand, the function of mode switching is realized through the double dead zone, on the one hand, the problems of large calculated amount and slow response of a single model prediction method are reduced, the calculated amount of a controller is reduced so as to improve the calculation speed, and on the other hand, the double dead zone function design is combined with the model prediction control, on the basis of realizing effective adjustment of the height of the vehicle body, the repeated opening and closing problem of the electromagnetic valve is reduced, the service life of the electromagnetic valve is prolonged, the oscillation phenomenon of the height of the vehicle body is reduced, and the driving safety is improved.
Drawings
FIG. 1 is a general flow diagram of a method for controlling the height of an air suspension vehicle according to the present invention;
FIG. 2 is a flow chart of a method for predicting vehicle height control based on a dual control dead zone air suspension model of the present invention.
Detailed Description
The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific examples, so that those skilled in the art can better understand the present invention and implement it, but the examples are not limited thereto.
The air suspension vehicle height control method, as shown in fig. 1 and 2, comprises the following steps:
Step 1, acquiring a vehicle running state parameter at the current moment:
The vehicle running state parameters at the current moment can be acquired through sensors, including the current moment vehicle speed (can be acquired through a vehicle speed sensor), the vehicle body heights of four wheels (can be acquired through four vehicle body height sensors respectively), the air bag air pressures of four air springs at each suspension (can be acquired through four air pressure sensors respectively), the vehicle body vertical acceleration, the vehicle body side inclination acceleration and the vehicle body pitch angle acceleration, wherein the four air springs are arranged between each wheel and the vehicle body to replace the positions of the spiral springs in the original suspension. In addition, vehicle body attitude signals including vehicle body vertical acceleration, vehicle body roll angle acceleration, vehicle body pitch angle acceleration and the like at the centroid can be acquired through a triaxial acceleration sensor.
And 2, determining the ideal control target and the sizes of the double control dead zones delta 1 and delta 2 according to the running state parameters of the vehicle at the current moment.
The ideal control target comprises a target vehicle body height, ideal vehicle body vertical acceleration, ideal vehicle body roll angle and ideal vehicle body pitch angle, and the acquired angular acceleration is calculated and converted to obtain the control target (each corresponding angle).
The invention reduces static errors by using the setting of the small dead zone delta 1, reduces the control frequent oscillation switching phenomenon caused by external disturbance by using the setting of the large dead zone delta 2, and the calculation formulas of the double control dead zones delta 1 and delta 2 are as follows:
Wherein v is the current vehicle speed, h d is the current target vehicle height, a, b, m and n are the small control dead zone vehicle speed gain coefficient, the small control dead zone target vehicle body height gain coefficient, the large control dead zone vehicle speed gain coefficient and the large control dead zone target vehicle body height gain coefficient (which can be determined according to the real vehicle experiment), c 1,c2 is the small control dead zone compensation factor and the large control dead zone compensation factor, respectively, and the fine tuning of the double control zones avoids the extreme condition of size conflict.
The air suspension vehicle body height control takes a vehicle body height signal, an air spring air bag air pressure signal, a vehicle body side inclination angle acceleration signal and a vehicle body pitch angle acceleration signal as control signal input, predicts an air suspension vehicle body height control strategy based on a model of a double control dead zone, and outputs a PWM electromagnetic valve control signal.
And 3, determining the deviation between the actual vehicle body height and the target vehicle body height according to the vehicle body height signal, and judging whether the large control dead zone delta 2 is exceeded or not: if the large control dead zone delta 2 is exceeded, the step 4 is entered; if the large control dead zone Δ 2 is not exceeded, step 7 is entered.
Step 4, discrete linearization of the air suspension model and establishment of a prediction model, specifically: the prediction model is as follows:
x(k+1)＝Ax(k)+Bu(k)
y(k)＝Cx(k)
Wherein x (k) is a suspension system state parameter at the current moment, including a vehicle body height at four wheels, air spring air bag pressure, a vehicle body roll angle acceleration and a vehicle body pitch angle acceleration, x (k+1) is a predicted suspension system state parameter of one time unit in the future, u (k) is a suspension system input quantity at the current moment (namely an air spring air bag pressure change quantity caused by control operation of an air solenoid valve), y (k) is a control target at the current moment, including a vehicle body height, a vehicle body vertical acceleration, a vehicle body roll angle and a vehicle body pitch angle, A, B and C are coefficient matrixes determined by vehicle attributes, and the vehicle attributes include parameters such as a vehicle body mass, a wheel stiffness, a damper damping and the like.
The description is as follows: the control target at the current time is to control the current size of the content, and the ideal control target is to control the ideal size of the content.
And 5, predicting the vehicle running state parameters of the corresponding time of N p time units in the future through a prediction model according to the vehicle running state parameters at the current time, and establishing a prediction matrix according to the predicted vehicle running state parameters so as to optimally solve the ideal suspension system input quantity, wherein the specific steps are as follows:
establishing a prediction matrix according to predicted values of vehicle running state parameters at corresponding moments of N p time units in the future:
wherein Y (k) is a predictive control target matrix of Y (k), U is a predictive system input matrix of U (k), And Θ is a coefficient matrix consisting of A, B, C;
By establishing evaluation indexes and optimizing and solving ideal suspension system input quantity according to a prediction matrix:
Wherein J is an evaluation index, Q is a weight matrix for expressing weight distribution of vehicle object states including vehicle body height, vehicle body vertical acceleration, vehicle body roll angle and vehicle body pitch angle, R is a weight matrix for expressing weight distribution of an inflation electromagnetic valve, a deflation electromagnetic valve and four switch electromagnetic valves for control input, N p is a prediction time, Y ref (k) is an ideal control target at the current moment, Y ref (k) is an ideal control target for predicting future conditions, Is the sum of the products of the squares of the elements of the matrix and the weights corresponding to the weight matrix Q,The sum of the products of the squares of the elements of the matrix and the weight corresponding to the weight matrix R is the ideal suspension system input quantity when J takes the minimum value.
Step 6, performing selective feedback correction according to the ideal suspension system input quantity and based on the small control dead zone delta 1: outputting control signals of all electromagnetic valves according to the ideal input quantity of the suspension system, and entering a step 7 if the deviation between the actual vehicle body height and the target vehicle body height is smaller than a small control dead zone delta 1; if the deviation is still greater than the small control dead zone delta 1, returning to the step 4, feeding back the latest input condition, updating the vehicle running state parameters of the control system, updating the prediction model, and performing prediction analysis calculation and control after correction.
And 7, judging whether an extreme phenomenon that the deviation oscillates too much in a small control dead zone delta 1 exists or not according to the deviation of the actual vehicle body height and the target vehicle body height and the change frequency, if so, entering the step 8, and if not, directly entering the step 9.
And 8, outputting a model prediction compensation control signal, for example, the output model prediction compensation control is to consider the influence of hysteresis and time hysteresis on the basis of the steps 4-5, determine the proportion according to the double control dead zones delta 1 and delta 2 and output the output value of the original prediction control in proportion.
And 9, performing pressure maintaining control, and outputting a normally closed PWM electromagnetic valve control signal of the electromagnetic valve to perform vehicle body height control.
In general, the actuator is a four switch solenoid valve connected to four air springs, an inflation solenoid valve connected to a high pressure air source, and a deflation solenoid valve connected to a low pressure air source:
When the controller outputs a deflation control signal, the switch electromagnetic valve of the air spring is opened, the deflation electromagnetic valve is opened, the inflation electromagnetic valve is closed, the air spring air bag is connected with a low-pressure air source, the air pressure of the air spring air bag is reduced, and the height of the air spring is reduced;
when the controller outputs an inflation control signal, the switch electromagnetic valve of the air spring is opened, the deflation electromagnetic valve is closed, the inflation electromagnetic valve is opened, the air spring air bag is connected with a high-pressure air source, the air pressure of the air spring air bag is enhanced, and the height of the air spring vehicle body is improved;
when the controller outputs a pressure maintaining control signal, the switch electromagnetic valve of the air spring is closed, the deflation electromagnetic valve is closed, the inflation electromagnetic valve is closed, and the air pressure of the air spring air bag is basically unchanged.
The prediction model is a model-based multi-target secondary optimization algorithm, a sampling value at unit sampling time, a discretization model and a prediction equation iterated by deformation are utilized, the prediction equation and an ideal control target are subjected to secondary planning, and an optimal control output value meeting constraint conditions is calculated at the moment. On the basis of the original model predictive control, the predictive model based on the double control dead zone uses an initial large control dead zone delta 2 as a precondition to determine and update a reference track, namely an ideal control target and the double control dead zone according to the current vehicle running state parameters including the vehicle speed; feedback correction is carried out based on the small control dead zone delta 1, namely, the size of the small control zone delta 1 of the double control zones is combined to carry out selective feedback and correction on the prediction model and the optimization calculation part; and compensation control based on the double control dead zone is performed in an extreme phenomenon of repeated high-frequency fluctuation which may occur in a small range of the control region.
Taking a constant-speed working condition as an example, a vehicle speed sensor collects a vehicle speed signal, a controller determines the current vehicle speed and the target vehicle height according to the current vehicle speed signal, and determines the size range of a current double-control dead zone, and the outputs of four vehicle height sensors, four air suspension air bag pressure sensors and three-axis acceleration sensors form current system state parameters. When the height deviation of the vehicle body exceeds the current large control dead zone, the controller performs model predictive control, controls each electromagnetic valve to perform inflation or deflation operation according to the requirement until the deviation is reduced to be in the small control dead zone, and then the vehicle body is converted to a pressure maintaining state, and outputs normally closed control signals of each electromagnetic valve; and when the deviation increases from the small control dead zone to the inside of the large control dead zone and does not exceed the large control dead zone, the solenoid valves are kept normally closed until the large dead zone is exceeded for control or the small dead zone is reentered. When an extreme condition occurs in which the vehicle body height fluctuates repeatedly at a high frequency in the control dead zone, model predictive compensation control is performed to reduce vibration. When the vehicle speed increases, the controller updates the current vehicle speed and reduces the target vehicle height according to the vehicle speed signal acquired by the vehicle speed sensor so as to adapt to the increase of the vehicle speed, and increases the size range of the double control dead zone, the follow-up control flow is unchanged, the tolerance to suspension disturbance is improved so as to reduce the operating frequency of the electromagnetic valve, the vehicle body height oscillation problem caused by frequent operation is reduced, and the operation stability and the running safety are improved. When the vehicle speed is reduced, the riding comfort is improved, and the control flow is the same.
The foregoing description is only of the preferred embodiments of the present invention, and is not intended to limit the scope of the invention, but rather is intended to cover any equivalents of the structures disclosed herein or modifications in equivalent processes, or any application, directly or indirectly, within the scope of the invention.

Claims (7)

1. The method for controlling the height of the air suspension vehicle body is characterized by comprising the following steps of:
step 1, acquiring a vehicle running state parameter at the current moment;
step 2, determining the ideal control target and the sizes of double control dead zones delta 1 and delta 2 according to the running state parameters of the vehicle at the current moment;
And 3, determining the deviation between the actual vehicle body height and the target vehicle body height according to the vehicle body height signal, and judging whether the large control dead zone delta 2 is exceeded or not: if the large control dead zone delta 2 is exceeded, the step 4 is entered; if the large control dead zone delta 2 is not exceeded, the step 7 is entered;
Step 4, discrete linearization of the air suspension model and establishment of a prediction model;
Step 5, predicting the vehicle running state parameters of the corresponding time of N p time units in the future through a prediction model according to the vehicle running state parameters at the current time; establishing a prediction matrix according to the predicted vehicle running state parameters so as to optimally solve the ideal suspension system input quantity;
Step 6, performing selective feedback correction according to the ideal suspension system input quantity and based on the small control dead zone delta 1: outputting control signals of all electromagnetic valves according to the ideal input quantity of the suspension system, and entering a step 7 if the deviation between the actual vehicle body height and the target vehicle body height is smaller than a small control dead zone delta 1; if the deviation is still greater than the small control dead zone delta 1, returning to the step 4, feeding back the latest input condition, updating the vehicle running state parameters of the control system, updating the prediction model, and performing prediction analysis calculation and control after correction;
Step 7, judging whether an extreme phenomenon that the deviation oscillates too much in a small control dead zone delta 1 exists or not according to the deviation of the actual vehicle body height and the target vehicle body height and the change frequency, if so, entering the step 8, and if not, directly entering the step 9;
Step 8, outputting a model predictive compensation control signal;
and 9, performing pressure maintaining control, and outputting a normally closed PWM electromagnetic valve control signal of the electromagnetic valve to perform vehicle body height control.
2. The method according to claim 1, wherein in step 1, the vehicle running state parameters at the present time include the vehicle speed at the present time, the vehicle body height at four wheels, the air bag pressures of four air springs at each suspension, the vehicle vertical acceleration, the vehicle roll angle acceleration, and the vehicle pitch angle acceleration.
3. The method of controlling the height of an air suspension vehicle according to claim 2, wherein in step 2, the ideal control target includes a target vehicle height, an ideal vehicle vertical acceleration, an ideal vehicle roll angle, and an ideal vehicle pitch angle.
4. A method for controlling the height of an air suspension vehicle according to claim 3, wherein in step 2, the calculation formulas of the double control dead zones Δ 1 and Δ 2 are as follows:
Wherein v is the current vehicle speed, h d is the current target vehicle height, a, b, m and n are the small control dead zone vehicle speed gain coefficient, the small control dead zone target vehicle body height gain coefficient, the large control dead zone vehicle speed gain coefficient and the large control dead zone target vehicle body height gain coefficient, and c 1,c2 is the small control dead zone compensation factor and the large control dead zone compensation factor, respectively.
5. The method according to claim 4, wherein in step 4, the prediction model is:
x(k+1)＝Ax(k)+Bu(k)
y(k)＝Cx(k)
Wherein x (k) is a suspension system state parameter at the current moment, including the vehicle body height at four wheels, the air pressure of four air spring air bags, the vehicle body roll angle acceleration and the vehicle body pitch angle acceleration, x (k+1) is a predicted suspension system state parameter of one time unit in the future, u (k) is a suspension system input quantity at the current moment, y (k) is a control target at the current moment, including the vehicle body height, the vehicle body vertical acceleration, the vehicle body roll angle and the vehicle body pitch angle, and A, B and C are coefficient matrixes determined by vehicle attributes.
6. The method for controlling the height of an air suspension vehicle according to claim 5, wherein in step 5, a prediction matrix is established according to predicted values of vehicle running state parameters at corresponding moments of N p time units in the future:
wherein Y (k) is a predictive control target matrix of Y (k), U is a predictive system input matrix of U (k), And Θ is a coefficient matrix consisting of A, B, C;
By establishing evaluation indexes and optimizing and solving ideal suspension system input quantity according to a prediction matrix:
Wherein J is an evaluation index, Q is a weight matrix for expressing weight distribution of vehicle object states including vehicle body height, vehicle body vertical acceleration, vehicle body roll angle and vehicle body pitch angle, R is a weight matrix for expressing weight distribution of an inflation electromagnetic valve, a deflation electromagnetic valve and four switch electromagnetic valves for control input, N p is a prediction time, Y ref (k) is an ideal control target at the current moment, Y ref (k) is an ideal control target for predicting future conditions, Is the sum of the products of the squares of the elements of the matrix and the weights corresponding to the weight matrix Q,The sum of the products of the squares of the elements of the matrix and the weight corresponding to the weight matrix R is the ideal suspension system input quantity when J takes the minimum value.
7. The method according to claim 6, wherein in step 8, the output model predictive compensation control is performed by taking the influence of hysteresis and time-lag into consideration on the basis of steps 4-5, and the output value of the original predictive control is outputted in proportion by determining the proportion based on the double control dead zones Δ 1 and Δ 2.
CN202410387634.0A 2024-04-01 2024-04-01 Air suspension vehicle height control method Pending CN118238564A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN120191162A (en) * 2025-04-10 2025-06-24 苏州麦哲轮汽车电子科技有限公司 An electronically controlled air suspension pitch control system and method based on MPC technology

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN120191162A (en) * 2025-04-10 2025-06-24 苏州麦哲轮汽车电子科技有限公司 An electronically controlled air suspension pitch control system and method based on MPC technology

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