CN103660991A - Method and system for controlling non-linear levitation of normal conducting magnetic-levitation train - Google Patents

Abstract

The invention discloses a method and system for controlling non-linear levitation of a normal conducting magnetic-levitation train. According to the method and system for controlling the non-linear levitation of the normal conducting magnetic-levitation train, the non-linear relationship among the levitation force, the levitation gap and the current of an electromagnet winding is obtained firstly through an experiment method or a finite element method, and a data table is established; levitation gap deviation is obtained by subtracting a levitation gap feedback value from a levitation gap expectation value, a levitation force expectation value is output after calculation is conducted through a levitation gap controller, table looking-up is conducted according to the levitation force expectation value and the levitation gap feedback value, a current expectation value is obtained through interpolation calculation, the current expectation value is input, current is applied to the electromagnet winding through a current controller, the current expectation value is tracked by the actual control current, as a result, an actual levitation force value can follow the levitation force expectation value, then a levitation gap can be kept close to the levitation gap expectation value, and the stable levitation control over the system is achieved. The method for controlling the non-linear levitation of the normal conducting magnetic-levitation train can be highly adaptable to levitation gaps and load change and can be easily achieved through programming, and the stability and the reliability of a levitation system can be improved.

Description

A kind of non-linear suspension control method of magnetic-levitation train and control system thereof often led

Technical field

The present invention relates to magnetic floating train suspending control method technical field, particularly a kind of non-linear suspension control method of magnetic-levitation train and control system thereof often led.

Background technology

The stable suspersion gap of often leading magnetic-levitation train is generally 8mm, and by analysis, when levitation gap variation range is within ± 2mm, and curent change scope is within ± 10A time, and suspension system can be similar to and be considered as linear system.Yet in practice, be subject to the restriction of engineering specifications, levitation gap variation range generally will reach 0～20mm left and right, and the variation range of electromagnet current can reach 0～100A, and the suspension system of therefore often leading magnetic-levitation train is a strongly non-linear system.

In order to realize the stable suspersion of system, traditional method is suspension system to be carried out near operation point to linearization, sets up inearized model, and then design suspension control system.This method is easy to realize, and can adopt classical control theory to carry out stability analysis and calculation of parameter, yet facts have proved, when there is larger fluctuation in the load variations (passengers quantity changes) of magnetic-levitation train or levitation gap, working state of system is away from predefined operation point, now adopt inearized model error larger, have a strong impact on stability and the reliability of system.

In order to make up the defect of traditional control method, some scholars introduce non-linear and intelligent control method in the suspension control of often leading magnetic-levitation train.But the general computing of these methods is complicated, control parameter acquiring difficulty, be difficult for realizing.

Therefore, how to solve traditional control method in the problem of suspension system controller performance degradation during away from operation point, and existing non-linear and intelligent control method computing complicated, be difficult to the problem that realizes, become those skilled in the art's important technological problems urgently to be resolved hurrily.

Summary of the invention

In view of this, the invention provides a kind of non-linear suspension control method of magnetic-levitation train of often leading, can make up the defect of traditional control method, fully adapt to the nonlinear characteristic of suspension system, there is again the feature that computing is simple, be easy to realization simultaneously.

The present invention also provides a kind of and has often led the non-linear suspension control system of magnetic-levitation train for what realize above-mentioned control method.

For achieving the above object, the invention provides following technical scheme:

Often lead the non-linear suspension control method of magnetic-levitation train, comprise step:

S1, by levitation gap sensor, obtain levitation gap value of feedback δ, by with levitation gap expectation value δ ^*deduct the deviation delta δ that levitation gap value of feedback δ obtains levitation gap, after the computing of levitation gap controller, export the expectation value F of lift force ^*;

S2, by the expectation value F of lift force ^*with levitation gap value of feedback δ, according to the nonlinear relationship data sheet between lift force, levitation gap and electromagnet winding current, and by interpolation arithmetic, obtain the expectation value i of electromagnet winding current ^*;

S3, by the expectation value i of electromagnet winding current ^*be input to current controller, this current controller puts on working control current i the winding of electromagnet after computing.

Above-mentioned steps can realize working control current i to electric current expectation value i ^*tracking, make lift force actual value F follow lift force expectation value F ^*thereby, control levitation gap and remain on levitation gap expectation value δ ^*near, realize the stable suspersion of system and control.

Preferably, the nonlinear relationship between lift force, levitation gap and electromagnet winding current measures by experiment in advance or Finite Element Method is obtained, and sets up data sheet according to above-mentioned nonlinear relationship.

A kind of non-linear suspension control system of magnetic-levitation train of often leading, for realizing the above-mentioned non-linear suspension control method of magnetic-levitation train of often leading, comprise levitation gap sensor, levitation gap deviation computing module, levitation gap controller, nonlinear relationship data sheet module, current controller and electromagnet that communication successively connects;

Described levitation gap sensor can obtain levitation gap value of feedback δ, and is outputed to described levitation gap deviation computing module;

Described levitation gap deviation computing module can be according to levitation gap expectation value δ ^*obtain the deviation delta δ of levitation gap with above-mentioned levitation gap value of feedback δ, and outputed to described levitation gap controller;

Described levitation gap controller can obtain according to the deviation delta δ of above-mentioned levitation gap the expectation value F of lift force ^*, and outputed to described nonlinear relationship data sheet module;

Described nonlinear relationship data sheet module can be according to the nonlinear relationship data sheet between lift force, levitation gap and electromagnet winding current, and by interpolation arithmetic the expectation value F by above-mentioned lift force ^*obtain the expectation value i of electric current with above-mentioned levitation gap value of feedback δ ^*, and outputed to described current controller;

Described current controller can be according to the expectation value i of electric current ^*obtain working control current i, and put on the winding of described electromagnet.

Such scheme can be realized working control current i to electric current expectation value i ^*tracking, make lift force actual value F follow lift force expectation value F ^*thereby, control levitation gap and remain on levitation gap expectation value δ ^*near, realize the stable suspersion of system and control.

From above-mentioned technical scheme, can find out, the non-linear suspension control method of magnetic-levitation train and the control system thereof often led provided by the invention, compare with traditional control method, this programme does not rely on the inearized model at place, operation point, therefore when there is larger fluctuation in the load variations (passengers quantity changes) of magnetic-levitation train or levitation gap, control model and still can keep higher precision, therefore can significantly improve stability and the reliability of system; Non-linearly compare with intelligent control method with existing, this programme computing is simple, is easy to programming and realizes, and can adopt classical control theory to carry out stability analysis and control the calculating of parameter, therefore has good practicality.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.

The suspension control system constructional drawing of Fig. 1 for adopting thought of the present invention to build; Wherein, δ is levitation gap value of feedback (being obtained by levitation gap sensor), δ ^*for levitation gap expectation value, Δ δ levitation gap deviation, F ^*for the lift force expectation value of exporting after the computing of levitation gap controller, i ^*for electromagnet winding current expectation value, i is the working control electric current of exporting to electromagnet, and F is the lift force actual value that electromagnet produces;

Fig. 2 is example for take the middle low-speed maglev train that applicant of the present invention was developed, and levitation gap is 8mm, when electric current changes from 0 to 60A, and the formula computing value of lift force and the contrast situation of three-dimensional finite element analysis value;

Fig. 3 is example for take the middle low-speed maglev train that applicant of the present invention was developed, and electric current is 30A, when levitation gap changes from 0 to 20mm, and the formula computing value of lift force and the contrast situation of three-dimensional finite element analysis value;

Fig. 4 is example for take the middle low-speed maglev train that applicant of the present invention was developed, and adopts the nonlinear relationship curve of levitation gap, electric current and lift force that dimensional finite element method obtains;

Fig. 5 is that levitation gap controller adopts pid algorithm, and current controller is while being equivalent to first order inertial loop, adopts the constructional drawing of the suspension control system that inventive concept builds;

Fig. 6 is that levitation gap expectation value is 8mm, while adopting respectively inventive concept and traditional control method, and the simulation result of levitation gap;

Fig. 7 is that levitation gap expectation value is 8mm, and at 1.5s, electromagnet is applied to certain load, while adopting respectively inventive concept and traditional control method, and the simulation result of levitation gap;

Fig. 8 is that levitation gap expectation value is 12mm, while adopting respectively inventive concept and traditional control method, and the simulation result of levitation gap.

The specific embodiment

For a concrete application example of the present invention, be described further below.

First illustrate that the inearized model that traditional suspension control method adopts has certain inaccuracy.

For a suspension system, the method for obtaining lift force mainly contains formula calculating, Finite Element Method and experiment measuring.Facts have proved, in various theoretical calculation methods, dimensional finite element method has taken into full account the impact of practical structures on Distribution of Magnetic Field, therefore meets most with actual conditions.Consider that experiment measuring lift force needs accurate experimental facilities simultaneously, obtain difficulty, experimental cost is high, and the present invention replaces experiment measuring value with three-dimensional finite element analysis value, contrasts with formula computing value.

The middle low-speed maglev train that applicant of the present invention was developed of take is example, and the nonlinear relationship curve of levitation gap, electric current and lift force that employing dimensional finite element method obtains as shown in Figure 4.

According to theory of electromagnetic field, the lift force analytical expression of magnetic suspension system is:

$F=\frac{{\mathrm{\μ}}_0{N}^{2}S}{4}{\left[\frac{i}{\mathrm{\δ}}\right]}^2---\left(1\right)$

Wherein, S is electromagnet pole area, and N is number of turns of winding, μ ₀for space permeability.

If the operation point of suspension system is (i ₀, δ ₀), Δ i, Δ δ are current change quantity and the levitation gap variable quantity that departs from operation point, F ₀equal weight suspension, lift force at the inearized model at place, operation point is:

F=F ₀+k _iΔi-k _zΔδ （2）

Wherein, $k_i=\frac{{\mathrm{\&mu;}}_0{N}^2{\mathrm{<figure-callout\; id="0"\; label="Si"\; filenames="HDA0000436291220000012.png,HDA0000436291220000022.png"\; state="\{\{state\}\}">Si</figure-callout>}}_0}{{{2\mathrm{\&delta;}}_0}^2},k_z=\frac{{\mathrm{\&mu;}}_0{N}^2{{\mathrm{<figure-callout\; id="0"\; label="Si"\; filenames="HDA0000436291220000012.png,HDA0000436291220000022.png"\; state="\{\{state\}\}">Si</figure-callout>}}_0}^2}{{{2\mathrm{\&delta;}}_0}^3},{\mathrm{<figure-callout\; id="0"\; label="F"\; filenames="HDA0000436291220000012.png,HDA0000436291220000022.png"\; state="\{\{state\}\}">F</figure-callout>}}_0=\frac{{\mathrm{\&mu;}}_0{N}^{2}S}{4}{\left(\frac{{\mathrm{<figure-callout\; id="0"\; label="i"\; filenames="HDA0000436291220000012.png,HDA0000436291220000022.png"\; state="\{\{state\}\}">i</figure-callout>}}_0}{{\mathrm{\&delta;}}_0}\right)}^2.$

The middle low-speed maglev train of developing for applicant of the present invention, the operation point current i of its suspension system ₀=30A, levitation gap δ ₀=8mm, Fig. 2 and Fig. 3 are respectively the contrast situation of formula (1) computing value, formula (2) computing value and three-dimensional finite element analysis value.Wherein, Figure 2 shows that levitation gap is 8mm, lift force situation of change when electric current changes from 0 to 60A, Figure 3 shows that electric current is 30A, lift force situation of change when levitation gap changes from 0 to 20mm.

By Fig. 2 and Fig. 3, can be found out, in system, during away from operation point, the deviation of formula (2) computing value and three-dimensional finite element analysis value can progressively increase.Yet in practice, when magnetic-levitation train is because load change, signal disturb, cross the factor impacts such as bend, suspension system is unavoidably away from operation point, and now the precision of inearized model certainly will reduce, thereby affects stability and the reliability of system.

In addition, related documents adopts the analytic expression shown in formula (1), and the inearized model shown in formula (2) has been carried out to nonlinear compensation, has designed corresponding suspension control method, and has obtained certain improvement effect.But from Fig. 2 and Fig. 3, can find out, at electric current hour, still there is larger error in large or levitation gap for formula (2) computing value and three-dimensional finite element analysis value, and therefore this method needs to be further improved.

As can be seen here,, all there is the defect that model error is larger in the control method based on formula (1) or formula (2) structure, and it is controlled effect and is difficult to further raising.

Given this, the present invention starts with from improving the precision of levitation force model, a kind of non-linear suspension control method of magnetic-levitation train of often leading is proposed, below in conjunction with the accompanying drawing in the embodiment of the present invention, technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.

On the basis of technique scheme of the present invention, from multiple, may scheme, select a kind of scheme herein, as specific embodiment, be described further, selected scheme comprises:

(1) levitation gap controller adopts pid algorithm;

(2) current controller is equivalent to first order inertial loop;

(3) take the middle low-speed maglev train that applicant of the present invention was developed is example, obtains the nonlinear relationship between lift force, levitation gap and electromagnet winding current, and set up data sheet by three-dimensional finite element analysis.It should be noted that, for the specific magnetic-levitation train of often leading, the above-mentioned process of obtaining nonlinear relationship and setting up data sheet only need to be carried out once when first enforcement.

The following describes while adopting above-mentioned embodiment the stability of suspension system and control parameter area.

In practice, lift force actual value F can lag behind lift force expectation value F ^*, this hysteresis is mainly caused by current controller, therefore current controller can be equivalent to first order inertial loop

wherein Ti is its time constant, can be obtained by experiment.

In Fig. 1, levitation gap controller adopts pid algorithm, and its transfer function is:

$G_c\left(s\right)=K_p+K_i\frac{1}{s}+K_{d}s$

The control block diagram of whole suspension control system can be equivalent to structure shown in Fig. 5.

Now, suspension control system closed loop transfer function, can be expressed as:

$\mathrm{\&Phi;}\left(s\right)=G_c\left(s\right)\frac{1}{T_{i}s+1}\frac{1}{{\mathrm{ms}}^2}=\frac{K_d{s}^2+K_{p}s+K_i}{{\mathrm{mT}}_i{s}^4+{\mathrm{ms}}^3+K_d{s}^2+K_{p}s+K_i}$

Wherein, K _p, K _i, K _dbe respectively ratio, integration and differentiation coefficient in pid algorithm.

The characteristic equation of above-mentioned transfer function is:

D(s)=mT _is ⁴+ms ³+K _ds ²+K _ps+K _i

According to the stability criterion of classical control theory, obtain the stable condition of closed loop system and be:

(1) T _i, m, K _d, K _p, K _iall be greater than 0.In reality these parameters be on the occasion of, therefore meet this requirement;

(2)

after control system structure is determined, T _ifor fixed value, and K _p, K _dbe adjustable, therefore, this requirement is satisfiable in practice;

（3）T _iK _p ²-K _dK _p+mK _i<0。By derivation, calculate, it be easy to show that this inequality has solution, repeats no more herein.

By above-mentioned analysis, can be obtained, the suspension control system that adopts thinking of the present invention to build is stable, and the scope of control parameter can be determined according to aforementioned stable condition.

It should be noted that, " pid algorithm " selected in the above specific embodiment of this programme is a kind of in many control algorithms, and levitation gap controller can adopt " pid algorithm ", also can adopt other algorithms such as " fuzzy control ", " Based Intelligent Control ";

Current controller can be equivalent to first order inertial loop, also can be equivalent to other similar link.

Adopt simulation technology to provide the control Contrast on effect situation of the present invention and traditional control method below.

In order to verify the preceence of the control method that the present invention proposes, adopt simulation result to carry out comparative illustration herein.Fig. 6 is the simulation result of levitation gap expectation value while being 8mm, can find out that method that the present invention proposes and the control effect of orthodox method are more or less the same.Explanation is at rated operation point place, and the present invention and orthodox method all can obtain good control effect.

Fig. 7 is that levitation gap expectation value is 8mm, and when 1.5s, apply the simulation result of certain load when (being equivalent to the passengers quantity increase of magnetic-levitation train), can find out the in the situation that of same load, while adopting inventive concept, the variable quantity of levitation gap is less, and the adjusting time is shorter.

Fig. 8 is the simulation result of levitation gap expectation value while being 12mm, can find out when system departs from operation point, and the control successful variation of orthodox method, and adopt inventive concept still can obtain good control effect.

Above-mentioned simulation result, illustrate that a kind of non-linear suspension control method of magnetic-levitation train of often leading that the present invention proposes does not rely on operation point inearized model, and levitation gap and load change are had to stronger comformability, its Combination property is better than traditional control method, is more suitable in strong jamming, nonlinear magnetic floating train suspending control system.

The embodiment of the present invention also provides a kind of non-linear suspension control system of magnetic-levitation train of often leading, for realizing the above-mentioned non-linear suspension control method of magnetic-levitation train of often leading, its core improvement is, comprises levitation gap sensor, levitation gap deviation computing module, levitation gap controller, nonlinear relationship data sheet module, current controller and electromagnet that communication successively connects;

Levitation gap sensor can obtain levitation gap value of feedback δ, and is outputed to levitation gap deviation computing module;

Levitation gap deviation computing module can be according to levitation gap expectation value δ ^*obtain the deviation delta δ of levitation gap with above-mentioned levitation gap value of feedback δ, and outputed to levitation gap controller;

Levitation gap controller can obtain according to the deviation delta δ of above-mentioned levitation gap the expectation value F of lift force ^*, and outputed to nonlinear relationship data sheet module;

Nonlinear relationship data sheet module can be according to the nonlinear relationship data sheet between lift force, levitation gap and electromagnet winding current, and by interpolation arithmetic the expectation value F by above-mentioned levitation gap expectation value δ and above-mentioned lift force ^*obtain the expectation value i of electric current ^*, and outputed to current controller;

Current controller can be according to the expectation value i of electric current ^*obtain working control current i, and put on the winding of electromagnet.

Such scheme can be realized working control current i to electric current expectation value i ^*tracking, make lift force actual value F follow lift force expectation value F ^*thereby, control levitation gap and remain on levitation gap expectation value δ ^*near, realize the stable suspersion of system and control.

In sum, the embodiment of the present invention provides often leads the non-linear suspension control method of magnetic-levitation train and control system thereof, in advance by experiment or Finite Element Method obtain lift force, nonlinear relationship between levitation gap and electromagnet winding current, and set up data sheet, levitation gap sensor obtains levitation gap value of feedback, levitation gap expectation value deducts the deviation that levitation gap value of feedback obtains levitation gap, after the computing of levitation gap controller, export lift force expectation value again, by lift force expectation value and levitation gap value of feedback, table look-up and obtain electric current expectation value by interpolation arithmetic, then be input to current controller, through overcurrent controller, electric current is put on to electromagnet winding, realize the tracking of working control electric current to electric current expectation value, make lift force actual value follow lift force expectation value, thereby controlling levitation gap remains near levitation gap expectation value, realizing the stable suspersion of system controls.This control method has stronger comformability for the situation of levitation gap and load change, is easy to programming and realizes, and can improve stability and the reliability of suspension system.

Above-mentioned explanation to the disclosed embodiments, makes professional and technical personnel in the field can realize or use the present invention.To the multiple modification of these embodiment, will be apparent for those skilled in the art, General Principle as defined herein can, in the situation that not departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention will can not be restricted to these embodiment shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.

Claims (3)

1. often lead the non-linear suspension control method of magnetic-levitation train, it is characterized in that, comprise step:

S1, by levitation gap sensor, obtain levitation gap value of feedback δ, by with levitation gap expectation value δ ^*deduct the deviation delta δ that levitation gap value of feedback δ obtains levitation gap, after the computing of levitation gap controller, export the expectation value F of lift force ^*;

S2, by the expectation value F of lift force ^*with levitation gap value of feedback δ, according to the nonlinear relationship data sheet between lift force, levitation gap and electromagnet winding current, and by interpolation arithmetic, obtain the expectation value i of electromagnet winding current ^*;

S3, by the expectation value i of electromagnet winding current ^*be input to current controller, this current controller puts on working control current i the winding of electromagnet after computing.

2. the non-linear suspension control method of magnetic-levitation train of often leading according to claim 1, it is characterized in that, nonlinear relationship between lift force, levitation gap and electromagnet winding current measures by experiment in advance or Finite Element Method is obtained, and sets up data sheet according to above-mentioned nonlinear relationship.

3. often lead the non-linear suspension control system of magnetic-levitation train for one kind, be used for realizing the non-linear suspension control method of magnetic-levitation train of often leading as claimed in claim 1 or 2, it is characterized in that, comprise levitation gap sensor, levitation gap deviation computing module, levitation gap controller, nonlinear relationship data sheet module, current controller and electromagnet that communication successively connects;

Described levitation gap sensor can obtain levitation gap value of feedback δ, and is outputed to described levitation gap deviation computing module;

Described levitation gap deviation computing module can be according to levitation gap expectation value δ ^*obtain the deviation delta δ of levitation gap with above-mentioned levitation gap value of feedback δ, and outputed to described levitation gap controller;

Described levitation gap controller can obtain according to the deviation delta δ of above-mentioned levitation gap the expectation value F of lift force ^*, and outputed to described nonlinear relationship data sheet module;

Described nonlinear relationship data sheet module can be according to the nonlinear relationship data sheet between lift force, levitation gap and electromagnet winding current, and by interpolation arithmetic the expectation value F by above-mentioned lift force ^*obtain the expectation value i of electric current with above-mentioned levitation gap value of feedback δ ^*, and outputed to described current controller;

Described current controller can be according to the expectation value i of electric current ^*obtain working control current i, and put on the winding of described electromagnet.

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