CN106183689A - The robust control system of a kind of air suspension of automobile and control method thereof - Google Patents

Abstract

The invention discloses robust control system and the control method thereof of a kind of air suspension of automobile, including sensor group, GPS navigation module, control module and actuator, control module receives sensor group and the signal of GPS navigation module collection, robust controller K is solved by setting up ECAS kinetic model, the minimum target of sum is weighted with suspension dynamic deflection, wheel vertical acceleration and vehicle body vertical acceleration three, obtain rigidity needed for air spring, and by the rigidity of the opening and closing regulation air spring of volume electromagnetic valve.The augmentation ECAS car model that the present invention sets up combines the change such as load, rigidity, road disturbance and ECAS automobile dynamics nominal model, and introduce that structured singular value μ is theoretical and small gain theorem this augmentation model is analyzed with comprehensively, the robust controller K solved can make ECAS system have robust performance while keeping robust stability, can be under conditions of inheriting original system overwhelming majority hardware, the controlling of air suspension is greatly improved.

Description

The robust control system of a kind of air suspension of automobile and control method thereof

Technical field

The present invention relates to a kind of field of automobile electronic control, be specifically related to a kind of air suspension robust control system and Control method.

Background technology

Air suspension (Air Suspension) was born in for 19 end of the centurys, compared with Leaf Spring Suspension, had anti-" S " firm Degree curve characteristic, can improve vehicle ride comfort and bodywork height can be made to keep the advantage such as constant.Therefore, in American-European automobile work Industry developed country, air suspension is widely used in coach luxury coach, heavy goods vehicle, medium truck, trailer, special vehicle (want by vibration isolation Ask high measuring truck, ambulance etc.) and luxurious passenger car.To 20th century the eighties, along with the development of electron controls technology, Occurring in that the Electronic Control air suspension of comparative maturity, it is compared with conventional air suspension, can promote car load further comprehensive Energy；And compared with full Active suspension, because it uses compressed air as working media, there is simple in construction, energy consumption low and use The features such as low cost.It is senior that Department of Transportation of China formulated regulation in " operating passenger car Type division and ranking " in 2010 Passenger vehicle must configure air suspension, it can be predicted that along with air suspension successful Application on China's coach luxury coach, will It is extended on the high special vehicle of heavy truck, semitrailer, cargo vehicle, anti-vibration performance requirement or even high-grade car, controlling party Face, also must go on track electronic, intelligentized.For Automobile Industry in China circle, air suspension not only has extensively Wealthy application prospect, it is often more important that can comparatively fast promote the class of domestic automobile, technical merit and the market competitiveness, development electricity Son controls air suspension technology, and to promotion China automotive engineering, economy and social development has important practical significance and far-reaching shadow Ring.

At present, although ECAS has reached initial purpose of design, but yet suffer from some technical problems and need to solve, its Performance and function are the most perfect, and especially for China's automotive suspension circle, ECAS key technology research and application push away Wide also have considerably long road to walk, and wherein one of problem is, ECAS automobile automobile load and suspension rate etc. in real work Often change, also has and is affected by external interference such as beam wind, road stones.Therefore, real ECAS automotive system is a collection ginseng Number change and the complicated nonlinear system of external interference composite factor impact.From the point of view of the open report of document, currently without maturation The control theory of nonlinear uncertain complication system and method may be directly applied to ECAS system, this will have a strong impact on and make The development of about ECAS automobile.Therefore, study model Parameters variation, unmodeled dynamiocs, time variation and external interference are to ECAS vapour The impact of car systematic function is significant to the automotive engineering level promoting China.

The impact on complex control system such as model parameter change, unmodeled dynamiocs and external interference, causes wide already The concern of big scientific worker.But, due to varying of control object, also do not set up unified, ripe theory.Just For the Electronic Control process of ECAS, relate to aerodynamic, Engineering Thermodynamics, automobile dynamics, electronics and modern times The subjects theory such as control theory, add model parameter change, external interference and the impact of unmodeled dynamiocs so that it controls system Designing and developing of system becomes extremely complex.It is crucial that how by road disturbance, model parameter change and non-linear ECAS automobile system System nominal model is associated reconstructing, and can isolate the impact of all perturbations (containing road disturbance, Parameters variation), and can solve The feedback controller adapted therewith.This is to ensure that ECAS system has the premise of robust stability and robust performance, and this is also The required problem solved of the present invention.

Summary of the invention

Goal of the invention: present invention aims to the deficiencies in the prior art, it is provided that the Shandong of a kind of air suspension of automobile Rod control system and control method thereof, make air suspension automobile can suppress the impact of the factor such as load change, road agitation, ECAS The robustness of system is greatly improved.

Technical scheme: the robust control system of a kind of air suspension of automobile, including sensor group, GPS navigation module, control Module and actuator, described sensor group is connected with the input port of control module respectively with GPS navigation module, control module Output port connect actuator, described actuator is the air spring controlled by volume electromagnetic valve；Described control module Receive sensor group and the signal of GPS navigation module collection, solve robust controller K acquisition by setting up ECAS kinetic model Rigidity needed for air spring, controls volume electromagnetic valve and is adjusted air spring.

Further, described sensor group includes air spring baroceptor, wheel vertical acceleration sensor, automobile speed Degree sensor, vehicle body vertical acceleration sensor and suspension dynamic deflection sensor, each sensor acquisition signal passes to control Module；Described air spring baroceptor gathers air spring air pressure signal, described wheel vertical acceleration sensor acquisition Wheel vertical acceleration, described automotive speed sensor gathers automobile driving speed, and described vehicle body vertical acceleration sensor is adopted Collection vehicle body vertical acceleration signal, described suspension dynamic deflection sensor acquisition suspension dynamic deflection signal.

Further, described air spring includes the different accessory air-space of two volumes and a main gas tank, and two accessory air-spaces divide Tong Guo not be connected with main gas tank with volume electromagnetic valve II by volume electromagnetic valve I, described air spring is in different initial gas pressure Time, reach rigidity needed for air spring by the opening and closing of volume adjusted electromagnetic valve I and volume electromagnetic valve II.

The control method of the robust control system of a kind of air suspension of automobile, comprises the following steps:

(1), during automobile starting, air suspension robust control system switches on power；

(2) after running car, sensor group carries out signal sampling, and the GPS navigation module location that carries out driving a vehicle determines car simultaneously Place road, it is compared with the standard path stored, determines pavement of road grade by control module；

(3) control module utilizes automobile driving speed and pavement of road rating calculation to go out wheel road excitation, sets up ECAS Kinetic model solves robust controller K, weights with suspension dynamic deflection, wheel vertical acceleration and vehicle body vertical acceleration three The minimum target of sum, solves the target suspension rate coordinating to mate with motoring condition；

(4) determine the target open and-shut mode of volume electromagnetic valve according to target suspension rate, and with the working as of volume electromagnetic valve Front state compares the respective state deviation of acquisition, and is adjusted；

(5) sensor group and GPS navigation module enter the next sampling period, control module repeat aforesaid regulated and controled Journey, and circulate with this, until running car stops.

Further, the structure of described robust controller K comprises the following steps:

1. application Lagrangian method sets up 1/4th ECAS Vehicle system dynamics models, has the feature that

$m_s\stackrel{\·\·}{x_2}=F-c({\stackrel{\·}{x}}_2-{\stackrel{\·}{x}}_1)$

$m_u{\stackrel{\·\·}{x}}_1=-F+c({\stackrel{\·}{x}}_2-{\stackrel{\·}{x}}_1)+K_t(x_1-x_0)$

$F=PA=\frac{m_a}{V}RTA=\frac{m_a}{x_2-x_1}RT$

In formula: m_sFor spring carried mass, x₂For spring charge material heart displacement, F is air spring force, and c is shock absorber damping, m_u For unsprung mass, x₁For barycenter displacement under spring, K_tFor tire stiffness, x₀For road excitation, m_aFor gaseous mass in air spring, R Gas constant, T air kelvin rating；

Test according to GB/T4970 1996 automobile test standard, comparative experiments knot under the conditions of identical road excitation Fruit and simulation result, the accuracy verifying 1/4th ECAS Vehicle system dynamics models with this and effectiveness；

2. set up the seven freedom ECAS Full Vehicle Dynamics differential equation by Newton method, and the differential equation passes through state space Realize

$\left\{\begin{array}{c}\stackrel{\·}{x}=Ax+Bu\\ y=Cx+Du\end{array}\right.$

In formula: A, B, C, D are control coefrficient matrix, x is state variable,For the first derivative of state variable, y is for surveying ECAS automotive performance variable, u for control input variable；

On the basis of ECAS whole vehicle model, build opened loop control generalized model P (s) under frequency domain, i.e.

P (s)=C (sI-A)^-1B

Introducing the uncertain matrix of Δ (s) and W (s) weight function thereof, the transmission function controlling to be input to control output is with adding Method uncertainty is described, and i.e. has

T_yu={ P (s)+W (s) Δ (s): | | Δ (s) | | ∞ ＜ 1}

It addition, be introduced back into performance uncertainty function Δ_f(s) and weight function W thereof_f(s)；Meanwhile, robust control to be solved is introduced Device K processed, constitutes closed-loop control system by closed-loop forming, and its transfer function matrix M (s) has a following form:

$M\left(s\right)=\left[\begin{array}{cc}{M}_{11}& M_{12}\\ M_{21}& M_{\mathrm{22}}\end{array}\right]\left[\begin{array}{cc}WK{(I-PK)}^{-1}& W{(I-PK)}^{-1}\\ W_f{(I-PK)}^{-1}& W_f{(I-PK)}^{-1}\end{array}\right]$

It is matrix M that control system has the sufficient and necessary condition of robust stability and robust performance₁₁At uncertain matrix Δ The lower structured singular value μ of effect is less than 1 and matrix M at uncertain matrix Δ_PThe lower structured singular value μ of effect, less than 1, i.e. has

μΔ(M₁₁) ＜ 1

${\mathrm{\&mu;}}_{{\mathrm{\&Delta;}}_p}\left(M\right)<1$

Wherein

${\mathrm{\&Delta;}}_p=\left[\begin{array}{cc}\mathrm{\&Delta;}& 0\\ 0& {\mathrm{\&Delta;}}_p\end{array}\right]$

3. in order to solve robust controller K, introduce scale matrix D, and its initial value is unit matrix

By D-K iterative method, find robust controller K (s), make to meet

$\left|\right|{\mathrm{D\&mu;}}_{{\mathrm{\&Delta;}}_P}\left(M\right)D^{-1}\left|\right|\&le;1$

Solve the robust controller K of ECAS automotive system.

Further, in step (4), the actual measurement atmospheric pressure value according to air spring and the target suspension rate of calculating gained, compare Spring under the different open and-shut mode of correspondence volume electromagnetic valve I, II during the air spring difference initial gas pressure stored in control module Rigidity travels through, determine with suspension needed for the immediate air spring rigidity of rigidity, the clearest and the most definite volume electromagnetic valve I and II Target open and-shut mode and be adjusted.

Beneficial effect: the present invention set up augmentation ECAS car model combine the change such as load, rigidity, road disturbance and ECAS automobile dynamics nominal model, and introduce that structured singular value μ is theoretical and this augmentation model is analyzed by small gain theorem With comprehensively, the robust controller K solved can make ECAS system have robust performance while keeping robust stability, it is possible to Under conditions of inheriting original system overwhelming majority hardware, the controlling of air suspension is greatly improved.

Accompanying drawing explanation

Fig. 1 is Control system architecture schematic diagram of the present invention；

Fig. 2 is the air spring rigidity performance plot of the present invention；

Fig. 3 is that the GPS of the present invention determines road surface model figure；

Fig. 4 is the analysis uncertain ECAS automotive system robust stability figure of the present invention；

Fig. 5 is the analysis uncertain ECAS automotive system robust performance figure of the present invention；

Fig. 6 be the robust controller K of the present invention solve flow chart；

Fig. 7 is control method flow chart of the present invention.

Detailed description of the invention

Below technical solution of the present invention is described in detail, but protection scope of the present invention is not limited to described enforcement Example.

Embodiment: the robust control system of a kind of air suspension of automobile, as it is shown in figure 1, sensor group and GPS navigation module Being connected with the input of control module respectively, the outfan of control module connects execution machine by control signal power amplification circuit Structure.Wherein, sensor group includes air spring baroceptor, wheel vertical acceleration sensor, automotive speed sensor, car Body vertical acceleration sensor and suspension dynamic deflection sensor；Air spring baroceptor gathers air spring air pressure signal, Wheel vertical acceleration sensor acquisition wheel vertical acceleration, automotive speed sensor gathers automobile driving speed, and vehicle body hangs down Vehicle body vertical acceleration signal, suspension dynamic deflection sensor acquisition suspension dynamic deflection signal is gathered to acceleration transducer；Above The signal of sensor acquisition and the framing signal of GPS navigation module pass to control module by the input of control module, Control module includes ADC, CPU and the DAC being sequentially connected with.

Actuator is the air spring controlled by volume electromagnetic valve, and this air spring constructions is characterized as: by two secondary gas Room and a main gas tank are constituted, and accessory air-space I is connected with main gas tank by volume electromagnetic valve I, accessory air-space II passes through volume electromagnetic valve II is connected with main gas tank, and accessory air-space I volume is unequal with accessory air-space II volume size.Volume electromagnetic valve is controlled by off and on I and volume electromagnetic valve II, air spring volume can be divided into 4 kinds of states.Therefore, keep in air spring initial gas pressure Under permanence condition, by combinatorial regulation volume electromagnetic valve I, volume electromagnetic valve II, it is bent that air spring has 4 kinds of different mechanics Line, as in figure 2 it is shown, the spring performance that 1. curve is turned off for volume electromagnetic valve I and volume electromagnetic valve II, 2. curve is volume electricity The spring performance that magnet valve I is opened and volume electromagnetic valve II cuts out, curve is 3. closed for volume electromagnetic valve I and volume electromagnetic valve II is opened The spring performance opened, the spring performance that 4. curve is all opened for volume electromagnetic valve I and volume electromagnetic valve II.According to spring rate it is Elastic characteristic and the derivative relation of displacement, for the ease of storage, change into its rigidity by the spring characteristic curve of air spring, and WithRepresent, initial gas pressure in wherein subscript Pa represents air spring, subscript I, II represent volume electromagnetic valve I and II open or Off status, 0 represents closedown, and 1 represents unlatching.Test gas pressure is under the conditions of 2bar, 2.1bar ..., 5.9bar and 6bar Spring performance, by being converted into the spring rate shown in table 1, and is stored in controller.

Table 1 spring air pressure, volume electromagnetic valve I, II state and spring rateRelation table

Vehicle power by power line respectively with sensor group, control module, control signal power amplification circuit and volume Electromagnetic valve I, volume electromagnetic valve II are connected, and power line both positive and negative polarity is connected to the positive terminal that automobile starting on and off switch controls Terminal and negative terminal.

The control method of the robust control system of above-mentioned air suspension of automobile, process is as follows:

(1), when automobile key inserts and starts on and off switch and turn to ON position, robust control system switches on power.

(2), after running car, sensor group carries out sampled signal, and GPS navigation module carries out driving location, sensor simultaneously Signal and gps signal flow to CPU.

(3) as it is shown on figure 3, GPS navigation module determines that vehicle travels place road and is sent to control system, control system It being compared with the standard in the road model storehouse stored, determine pavement of road grade, CPU utilizes car speed to sense Automobile driving speed and pavement grade that device is measured calculate wheel road excitation, set up ECAS kinetic model and solve robust Controller K.

Concrete operations are as follows:

A, set up 1/4th ECAS Vehicle system dynamics models by Lagrangian method:

$m_s\stackrel{\&CenterDot;\&CenterDot;}{x_2}=F-c({\stackrel{\&CenterDot;}{x}}_2-{\stackrel{\&CenterDot;}{x}}_1)$

$m_u{\stackrel{\&CenterDot;\&CenterDot;}{x}}_1=-F+c({\stackrel{\&CenterDot;}{x}}_2-{\stackrel{\&CenterDot;}{x}}_1)+K_t(x_1-x_0)$

$F=PA=\frac{m_a}{V}RTA=\frac{m_a}{x_2-x_1}RT$

In formula: m_gSpring carried mass, x₂Spring charge material heart displacement, F air spring force, c shock absorber damping, m_uUnsprung mass, x₁Barycenter displacement under spring, k_tTire stiffness, x₀Road excitation, m_aGaseous mass in air spring, R gas constant, T air is absolute Temperature value, V is air spring volume, and A is air spring effective area.

B, according to GB/T4970 1996 automobile test standard, carry out two-freedom 1/4th ECAS car model examination Test, and compare with the simulation result under the conditions of identical excitation, checking 1/4th ECAS Vehicle system dynamics models Effectiveness.

C, set up seven freedom ECAS Full Vehicle Dynamics nominal plant model P by Newton method, the differential equation pass through state space Realize:

$\left\{\begin{array}{c}\stackrel{\&CenterDot;}{x}=Ax+Bu\\ y=Cx+Du\end{array}\right.$

In formula: A, B, C, D are control coefrficient matrix, x is state variable, and u is for controlling input variable.

As shown in Figure 4, kinetics nominal plant model P and diagonal arrangement uncertainty block Δ (s) and weight function W (s) thereof are entered Row association reconstruct, builds ECAS feedback control system P with uncertain Δ (s)；Concrete, make ECAS Full Vehicle Dynamics mould Type transmission function meets addition functor and describes, i.e.

T_yu={ P (s)+W (s) Δ (s): | | Δ (s) | |_∞＜ 1}

In formula: P (s)=C (sI-A)^-1B, Δ (s) is uncertain block, and W (s) is weight function.

It addition, as it is shown in figure 5, be re-introduced into uncertain block Δ_f(s) and weight function W thereof_fS () builds one and increases block diagonal angle Structure Δ_P, meanwhile, introduce robust controller K, constitute closed-loop control system, there is transfer function matrix M (s), and exist

$M\left(s\right)=\left[\begin{array}{cc}{M}_{11}& M_{12}\\ M_{21}& M_{\mathrm{22}}\end{array}\right]\left[\begin{array}{cc}WK{(I-PK)}^{-1}& W{(I-PK)}^{-1}\\ W_f{(I-PK)}^{-1}& W_f{(I-PK)}^{-1}\end{array}\right]$

Utilizing structured singular value μ to analyze the robust stability of feedback control system P, analysis is made up of P and K feedback control Transfer function matrix M is at block diagonal arrangement Δ_PRobust performance under She Dong, determines that structured singular value μ has robust stability With infimum and the supremum of robust performance, it is knot that control system has the sufficient and necessary condition of robust stability and robust performance Structure singular value μ meets following relation

μ_Δ(M₁₁) ＜ 1

${\mathrm{\&mu;}}_{{\mathrm{\&Delta;}}_p}\left(M\right)<1$

Wherein

${\mathrm{\&Delta;}}_p=\left[\begin{array}{cc}\mathrm{\&Delta;}& 0\\ 0& {\mathrm{\&Delta;}}_p\end{array}\right]$

By D-K iterative method, find robust controller K (s) so that it is meet

$\left|\right|D{\mathrm{\&mu;}}_{{\mathrm{\&Delta;}}_P}\left(M\right)D^{-1}\left|\right|\&le;1$

The concrete solution procedure of robust controller K as shown in Figure 6, introduces scale matrix D, and initial value is that unit is to angular moment Battle array, i.e.

First fix D, ask∞ control problem, it is thus achieved that initial K (s)；

Fix K again, askConvex optimization problem, it is thus achieved that D1；

Relatively D and D1, if both differences meet required precision, then the controller K 2. obtained by step is robust control Device processed, otherwise, makes D=D1, return to the 2. step proceed iteration, until finding result.

(4) as it is shown in fig. 7, the regulation process being equipped with the ECAS suspension of robust controller K is: by GPS module signal, vapour Vehicle speed sensor signal, vehicle body vertical acceleration signal, suspension dynamic deflection sensor signal and vehicle bridge acceleration transducer letter Number as controlling input signal, the ECAS Full Vehicle Dynamics model set up based on step c, robust controller K will scratch so that suspension is dynamic Degree, dynamic wheel load and barycenter vertical acceleration three weight the minimum object function of sum, with suspension rate as unknown variable Solve, obtain the rigidity value required for suspension.With the surveyed atmospheric pressure value of air spring baroceptor, required suspension rate value By look-up table, table 1 is traveled through, it may be determined that go out with suspension needed for the immediate air spring rigidity of rigidityAgain withSpecify volume electromagnetic valve I and the dbjective state of volume electromagnetic valve II, be such as 00,01,10 or 11.Then, by volume electricity The dbjective state of magnet valve I and volume electromagnetic valve II is stored in the current state of CPU and compares with it, if entirely consistent, then holds Long-pending electromagnetic valve I and volume electromagnetic valve II are maintained the statusquo；If it is inconsistent, volume electromagnetic valve devious is regulated and controled, example If current state is 00, and dbjective state requires to be 10, then controller can make volume electromagnetic valve I be transferred to unlatching by former closed mode And keep, and volume electromagnetic valve II keeps former closed mode；Other situations are similar to this, repeat the most one by one.

(5), after unified regulation and control end cycle of above-mentioned ECAS suspension system, sensor group will enter next sampling period, in control After there is new change in input signal processed, robust controller K work process as the regulation process described by step (4), then The secondary state to volume electromagnetic valve I and volume electromagnetic valve II is adjusted, and moves in circles with this, until automobile stops traveling is Only.

Claims (6)

1. the robust control system of an air suspension of automobile, it is characterised in that: include sensor group, GPS navigation module, control Module and actuator, described sensor group is connected with the input port of control module respectively with GPS navigation module, control module Output port connect actuator, described actuator is the air spring controlled by volume electromagnetic valve；Described control module Receive sensor group and the signal of GPS navigation module collection, solve robust controller K acquisition by setting up ECAS kinetic model Rigidity needed for air spring, controls volume electromagnetic valve and is adjusted air spring.

The robust control system of air suspension of automobile the most according to claim 1, it is characterised in that: described sensor group bag Include air spring baroceptor, wheel vertical acceleration sensor, automotive speed sensor, vehicle body vertical acceleration sensor With suspension dynamic deflection sensor, each sensor acquisition signal passes to control module；Described air spring baroceptor is adopted Collection air spring air pressure signal, described wheel vertical acceleration sensor acquisition wheel vertical acceleration, described car speed passes Sensor gathers automobile driving speed, described vehicle body vertical acceleration sensor acquisition vehicle body vertical acceleration signal, described suspension Dynamic deflection sensor acquisition suspension dynamic deflection signal.

The robust control system of air suspension of automobile the most according to claim 1, it is characterised in that: described air spring bag Including two different accessory air-spaces of volume and a main gas tank, two accessory air-spaces are respectively by volume electromagnetic valve I and volume electromagnetic valve II is connected with main gas tank, and described air spring is when different initial gas pressure, by volume adjusted electromagnetic valve I and volume electricity The opening and closing of magnet valve II reaches rigidity needed for air spring.

The control method of the robust control system of air suspension of automobile the most according to claim 1, it is characterised in that: include Following steps:

(1), during automobile starting, air suspension robust control system switches on power；

(2) after running car, sensor group carries out signal sampling, and the GPS navigation module location that carries out driving a vehicle determines vehicle institute simultaneously At road, it is compared with the standard path stored, determines pavement of road grade by control module；

(3) control module utilizes automobile driving speed and pavement of road rating calculation to go out wheel road excitation, sets up ECAS power Learn model solution robust controller K, weight sum with suspension dynamic deflection, wheel vertical acceleration and vehicle body vertical acceleration three Minimum target, solves the target suspension rate coordinating to mate with motoring condition；

(4) determine the target open and-shut mode of volume electromagnetic valve according to target suspension rate, and with the current shape of volume electromagnetic valve State compares the respective state deviation of acquisition, and is adjusted；

(5) sensor group and GPS navigation module enter the next sampling period, and control module repeats aforesaid regulation process, and Circulate with this, until running car stops.

The control method of the robust control system of air suspension of automobile the most according to claim 4, it is characterised in that: described The structure of robust controller K comprises the following steps:

1. application Lagrangian method sets up 1/4th ECAS Vehicle system dynamics models, has the feature that

$m_s\stackrel{\&CenterDot;\&CenterDot;}{x_2}=F-c({\stackrel{\&CenterDot;}{x}}_2-{\stackrel{\&CenterDot;}{x}}_1)$

$m_u{\stackrel{\&CenterDot;\&CenterDot;}{x}}_1=-F+c({\stackrel{\&CenterDot;}{x}}_2-{\stackrel{\&CenterDot;}{x}}_1)+K_t(x_1-x_0)$

$F=PA=\frac{m_a}{V}RTA=\frac{m_a}{x_2-x_1}RT$

In formula: m_sFor spring carried mass, x₂For spring charge material heart displacement, F is air spring force, and c is shock absorber damping, m_uFor spring Lower quality, x₁For barycenter displacement under spring, K_tFor tire stiffness, x₀For road excitation, m_aFor gaseous mass in air spring, R gas Constant, T air kelvin rating；

Test according to GB/T4970 1996 automobile test standard, under the conditions of identical road excitation comparative experiments result with Simulation result, the accuracy verifying 1/4th ECAS Vehicle system dynamics models with this and effectiveness；

2. set up the seven freedom ECAS Full Vehicle Dynamics differential equation by Newton method, and the differential equation passes through state space realization

$\left\{\begin{array}{c}\stackrel{\&CenterDot;}{x}=Ax+Bu\\ y=Cx+Du\end{array}\right.$

In formula: A, B, C, D are control coefrficient matrix, x is state variable,For the first derivative of state variable, y is measurable ECAS automotive performance variable, u is for controlling input variable；

On the basis of ECAS whole vehicle model, build opened loop control generalized model P (s) under frequency domain, i.e.

P (s)=C (sI-A)^-1B

Introduce the uncertain matrix of Δ (s) and W (s) weight function thereof, control to be input to the transmission function addition of control output not Definitiveness is described, and i.e. has

T_yu={ P (s)+W (s) Δ (s): | | Δ (s) | |_∞＜ 1}

It addition, be introduced back into performance uncertainty function Δ_f(s) and weight function W thereof_f(s)；Meanwhile, robust controller to be solved is introduced K, constitutes closed-loop control system by closed-loop forming, and its transfer function matrix M (s) has a following form:

$M\left(s\right)=\left[\begin{array}{cc}{M}_{11}& M_{12}\\ M_{21}& M_{22}\end{array}\right]=\left[\begin{array}{cc}WK{\left(I-PK\right)}^{-1}& W{\left(I-PK\right)}^{-1}\\ W_f{\left(I-PK\right)}^{-1}& W_f{\left(I-PK\right)}^{-1}\end{array}\right]$

It is matrix M that control system has the sufficient and necessary condition of robust stability and robust performance₁₁In uncertain matrix Δ effect Lower structured singular value μ is less than 1 and matrix M at uncertain matrix Δ_PThe lower structured singular value μ of effect, less than 1, i.e. has

μ_Δ(M₁₁) ＜ 1

${\mathrm{\&mu;}}_{{\mathrm{\&Delta;}}_p}\left(M\right)<1$

Wherein

${\mathrm{\&Delta;}}_p=\left[\begin{array}{cc}\mathrm{\&Delta;}& 0\\ 0& {\mathrm{\&Delta;}}_p\end{array}\right]$

3. in order to solve robust controller K, introduce scale matrix D, and its initial value is unit matrix

By D-K iterative method, find robust controller K (s), make to meet

$\left|\right|{\mathrm{D\&mu;}}_{{\mathrm{\&Delta;}}_P}\left(M\right)D^{-1}\left|\right|\&le;1$

Solve the robust controller K of ECAS automotive system.

The control method of the robust control system of air suspension of automobile the most according to claim 4, it is characterised in that: step (4) the actual measurement atmospheric pressure value according to air spring and the target suspension rate of calculating gained in, the sky of storage in comparison control module During air spring difference initial gas pressure, the spring rate under the different open and-shut mode of correspondence volume electromagnetic valve I, II travels through, and determines Air spring rigidity immediate with rigidity needed for suspension, the target open and-shut mode of the clearest and the most definite volume electromagnetic valve I and II is gone forward side by side Row regulation.