CN202421881U - Real-time monitoring device for controlling loop performance - Google Patents

Abstract

The utility model relates to the control system performance evaluating technology field, particularly to a real-time monitoring device for controlling loop performance. The real-time monitoring device comprises a data acquisition module, a preprocessing module, a real-time trend extracting module, a real-time state identifying module, a real-time delay estimating module, a real-time performance calculating module, and a real-time monitoring module, wherein the data acquisition module is respectively connected with the preprocessing module, the real-time trend extracting module, the real-time delay estimating module, and the real-time performance calculating module; the preprocessing module is connected with the real-time monitoring module; the real-time trend extracting module is respectively connected with the real-time state identifying module and the real-time performance calculating module; the real-time state identifying module is connected with the real-time performance calculating module; the real-time delay estimating module is connected with the real-time performance calculating module; and the real-time performance calculating module is connected with the real-time monitoring module. The real-time monitoring device of the utility model realizes the real-time monitoring over the performance of a control system and provides convenience for engineering technicians to master the performance of a control system.

Description

A kind of control loop performance real time monitoring device

Technical field

The utility model belongs to the performance evaluation technical field of control system, relates in particular to a kind of control loop performance real time monitoring device.

Background technology

The energy consumption of current China per GDP and pollutant emission level are also apparently higher than developed country.Along with the development of China's electric utility, fired power generating unit will be born prior energy-saving and emission-reduction responsibility.For this reason,, also must take effective measures the operation level that improves unit, to guarantee the safety of unit, economy, environmental protection operation except purchasing advanced generating set.Be not only power industry; The important task that the whole industrial system of China all is faced with energy-saving and emission-reduction, enhances productivity; The real-time performance of control system is kept watch on (Real-time Control Performance Monitoring, RCPM) technology a kind of solution route cost-effectively of can yet be regarded as.Simultaneously, RCMP is the change of foreseeing system performance in advance, the early warning system fault, and the performance of elevator system provides effective platform.

According to statistics, exist the problem of poor performance at current a lot of industrial control unit (ICU)s, this ratio is up to 60%; Simultaneously along with production-scale expansion; The feeder number of control system is more and more, and it is unrealistic also unreasonable to do maintenance test by the people merely, and when the degradation of control system; Not only the quality of product can not get guaranteeing but also can cause the reduction in production equipment life-span, and serious also possibly produce beyond thought accident; On the other hand, even if the operation at the beginning of performance better controlled device, along with the prolongation of service time, controller also can wear out, control performance can correspondingly reduce; Moreover be many-sided for the reason of the potential degeneration of controller; At first be exactly current disturbance and dead band; And system other dynamically as irreversible zero point etc.; What controller parameter was adjusted besides is improper, also has strain, the fault of equipment, the hardware failure of control system etc. all can become the potential cause that controller performance is degenerated.If can keep watch on effectively to the performance of control system, will improve its work efficiency greatly, reduce production costs, improve the validity of control.

It is one of fundamental purpose of control system performance evaluation and diagnosis that the problem that control loop is existed proposes early stage identification and diagnosis, and production run is carried out real-time supervision, provides prospective instruction to the slip-stick artist at scene.And lack necessary evaluation means and evaluation method, then can only be etc. could find after problem occurs, if we can make diagnosis in early days; So, can be through controller parameter adjust the controller parameter hardware maintenance again; Use new alternative control algolithm; Postpone perhaps to eliminate the part disturbance through process correction minimizing, use feedforward, remedial measuress such as change performance variable make the performance of system reach corresponding requirement.Therefore, the correlative study in this field of controller performance supervision receives much attention.

Summary of the invention

Be difficult to make performance evaluation and lack deficiency such as evaluation method to the performance of mentioning existing control system in the above-mentioned background technology, the utility model provides a kind of control loop performance real time monitoring device.

The technical scheme of the utility model is; A kind of control loop performance real time monitoring device is characterized in that this device comprises data acquisition module, pre-processing module, real-time tendency extraction module, real-time status discrimination module, real time delay estimation module, real-time performance computing module and real time monitoring module;

Said data acquisition module is connected with pre-processing module, real-time tendency extraction module, real time delay estimation module and real-time performance computing module respectively; Pre-processing module is connected with the real time monitoring module; The real-time tendency extraction module is connected with the real-time performance computing module with the real-time status discrimination module respectively; The real-time status discrimination module is connected with the real-time performance computing module; The real time delay estimation module is connected with the real-time performance computing module; The real-time performance computing module is connected with the real time monitoring module;

Said real-time tendency extraction module passes through from real-time data acquisition module reading of data, and the trend of extract real-time service data is as the input of state estimation module and real-time performance computing module;

As input, the current time delay of computing system is used for the performance of computing system to said real-time status discrimination module as the input of control system performance evaluation with real-time running data.

The utility model decomposes error through data processing after extracting through trend, obtains the randomness error component and the ascertainment error component of error.Randomness component computing system through error is performance index at random, the determinacy performance index of the determinacy component computing system through error.

The described control system system performance of the utility model real time monitoring technology path is clear, method is practical, is easy to engineering technical personnel and in reality, uses and realize.

Description of drawings

Fig. 1 keeps watch on for real-time performance;

Fig. 2 extracts process flow diagram for real time data trend;

Fig. 3 is for postponing the estimation module step;

Fig. 4 is the performance evaluation step.

Embodiment

Below in conjunction with accompanying drawing, preferred embodiment is elaborated.Should be emphasized that following explanation only is exemplary, rather than scope and application thereof in order to limit the utility model.

Be the performance of real time monitoring control loop, to promote the controlling level of control system, overall plan and concrete realization technology that the utility model provides the control loop real-time performance to estimate.

Real-time performance is kept watch on the implementation procedure of RCPM: at first be through the real-time tendency of extract real-time service data and then the running status of judgement system, simultaneously through the current time delay of real time data computing system.Postponing, trend is selected the performance index at random and the determinacy performance index of suitable algorithm computing system under the known situation of state.Simultaneously can be to carrying out variance analysis through pretreated real time data, power spectrumanalysis, standard deviation analysis, autocorrelation analysis, and then the performance of comprehensive surveillance.

The flow process of the utility model is as shown in Figure 1.Comprise: data acquisition module, pre-processing module, real-time tendency extraction module, real-time status discrimination module, real time delay estimation module, real-time performance computing module and real time monitoring module.Wherein:

The real-time tendency extraction module, through from real-time data acquisition module reading of data, the trend of extract real-time service data is as the input of state estimation module and real-time performance computing module;

The real-time status discrimination module, as input, the current time delay of computing system is used for the performance of computing system as the input of control system performance evaluation with real-time running data;

The real-time performance computing module is with the output of the output of the output of data acquisition module, real time delay estimation module, the real-time status estimation module performance as the input calculating control system.

Concrete module realizes as follows:

1, real-time tendency extraction module

The mode that real-time tendency extracts through sectional linear fitting in the utility model realizes.The trend of each section is represented with the point on the linear model of this section optimum.The trend of each section is combined into total trend.Wherein the linear segmented standard is based on the average (SSE, Sum of Square Error) of error of fitting quadratic sum.Concrete enforcement is following:

At current time t; Current linear model is used vector representation, is designated as

predicted value

that the value of reading in is obtained according to current linear model be:

$(\hat{y}\left(t\right)-{\hat{y}}_0\left(i\right))(t_e\left(i\right)-t_0\left(i\right))=({\hat{y}}_e\left(i\right)-{\hat{y}}_0\left(i\right))(t-t_0\left(i\right))---\left(1\right)$

Wherein:

t ₀(i) be this section initial time;

is the predicted value of this section initial time;

t _e(i) be this section end moment;

is this section end predicted value constantly.

The error of calculation:

$e\left(t\right)=y\left(t\right)-\hat{y}\left(t\right)---\left(2\right)$

Wherein:

E (t) is a t error constantly;

Y (t) is a t actual value constantly.

Calculate the SSE index of present segment:

$\mathrm{SSE}\left(i\right)=\frac{1}{n}\underset{j=t_0\left(i\right)}{\overset{t}{\mathrm{\Σ}}}e{\left(j\right)}^2---\left(3\right)$

Wherein:

N is the data number, n=(t-t ₀(i))/T _s

T _sBe the sampling time.

SSE and both relatively have three kinds of situation:

1) SSE≤s ₁, model is constant;

2) s ₁＜SSE≤s ₂Be that its moment and value are deposited in the exceptional value group;

3) SSE＞s ₂, carry out model modification, obtain new model after, SSE zero setting, the exceptional value array is put sky.

Obtained the linear model of this section, will bring into the time get final product the trend of service data of this section.Obtain the trend of each section by that analogy, the trend combination with each section obtains total trend completion trend extraction again.Total realization that its real-time tendency extracts is as shown in Figure 2.

2, real-time status discrimination module

After having extracted trend, can define three slopes through present segment (i section) and the last period (i-1 section):

$k=\frac{{\hat{y}}_e\left(i\right)-{\hat{y}}_e(i-1)}{t_e\left(i\right)-t_e(i-1)}---\left(3\right)$

$k_d=\frac{{\hat{y}}_0\left(i\right)-{\hat{y}}_e(i-1)}{t_0\left(i\right)-t_e(i-1)}=\frac{{\hat{y}}_0\left(i\right)-{\hat{y}}_e(i-1)}{T_s}---\left(4\right)$

$k_s=\frac{{\hat{y}}_e\left(i\right)-{\hat{y}}_0\left(i\right)}{t_e\left(i\right)-t_0\left(i\right)}---\left(5\right)$

Wherein:

K is total slope;

k _dFor being interrupted slope;

k _sFor this slope over 10;

is respectively the predicted value of i-1 section;

t _e(i-1) be the end moment of i section.

Make a decision also through three slopes of running state information that comprised system and need select threshold value.The selection of threshold value realizes that through selecting the slope inclination angle stable state can be thought less than θ in the inclination angle of slope, when it then thinks transition greater than θ d, marginally then thinks gradual change.Concrete differentiate shown in Figure 2ly, it is stable state that the status information that comprises through different three slope value and symbol makes up the current running status of acquisition system, dynamically (positive step is born step, and wink increases, and wink subtracts, and is cumulative, decrescence) in the sort of state.

The condition discrimination table that table 1 provides is realized the real-time status differentiation.The state of judging system through the value and the symbol of slope.

Table 1

3, real time delay estimation module

General type for general its pulsed transfer function of system is following:

$G\left(z\right)=\frac{{\mathrm{\β}}_1+{\mathrm{\β}}_2{z}^{-1}+\·\·\·+{\mathrm{\β}}_m{z}^{-m+1}}{1+{\mathrm{\α}}_1{z}^{-1}+\·\·\·+{\mathrm{\α}}_n{z}^{-n}}{z}^{d+1}---\left(6\right)$

Wherein:

ψ (t) is an input vector, ψ (t)=[y (t-1) ... ,-y (t-n), u (t-d-1) ... U (t-d-m)];

is coefficient vector,

ε (t) is an evaluated error.

Concrete delay estimating step is following:

At first, by up-to-date probability density function in the delay at maximum probability place as current delay, provide input vector.

The parameter of estimating system is employed at this real-time least-squares algorithm then,

$\widehat{\mathrm{\ψ}}\left(k\right)=[-y(k-1),\·\·\·,-y(k-n),u(k-d-1),\·\·\·u(k-d-m)]---\left(8\right)$

$P\left(k\right)=\frac{1}{{\mathrm{\ρ}}^2}\mathrm{pI}-K\left(k\right)\widehat{\mathrm{\ψ}}\left(k\right)]P(k-1)---\left(10\right)$

$K\left(k\right)=\frac{P(k-1)\widehat{\mathrm{\ψ}}\left(k\right)}{\widehat{\mathrm{\ψ}}\left(k\right)P(k-1)\widehat{\mathrm{\ψ}}\left(k\right)+{\mathrm{\ρ}}^2}---\left(11\right)$

Wherein:

is the predicted value of input and output vector;

U (k) is a controlled quentity controlled variable;

is the estimated value of coefficient vector;

K (k) is a correction factor;

P (k) is a variance matrix;

ρ is a forgetting factor;

I is a unit matrix;

Afterwards, confirm the optimizing space of delay through existing probability density function.

In this optimizing interval, through minimize losses function: J (k)=ρ ²J (k-1)+ε ²(t), obtain current delay estimated value just

Add new delay and upgrade probability density function, the length of delay at maximum probability place is as the delay estimated value

of current time

4, real-time performance computing module

Obtaining postponing through postponing estimation module, obtain state through the condition discrimination module, obtain after the trend through the trend extraction module, can be through the performance of following steps computing system:

At first, postpone for boundary will be output y be divided into two parts y ₁And y ₂, wherein:

y ₁＝y(1)，…y(d)

(12)

y ₂＝y(d+1)，y(d+2)，…

Then, extract y according to the aforesaid algorithm of the utility model ₂Trend term y ' ₂The random perturbation of system is to the influence of tracking error after the computing relay:

e′ ₂＝y ₂-y′ ₂ (13)

Wherein:

E ' ₂For postponing tracking error in the time period later;

In conjunction with within postponing with postpone after the randomness disturbance following to the randomness component that the influence of tracking error can get tracking error:

$\mathrm{es}\left(i\right)=\left\{\begin{array}{cc}y\left(i\right)-y\left(0\right)& i＜d\\ e_2^{\′}(i-d+1)& i\≥d\end{array}\right.---\left(14\right)$

Wherein:

Es (i) is the randomness error component;

Y (0) is the value before the set point change, and the system responses that following formula is illustrated in postponing is caused by random perturbation fully, and its influence to systematic error is tried to achieve through step (2) after postponing.

After obtaining es, through the minimum variance of FCOR (Filtering and subsequent Correlation) algorithm or difference ARMA model ARIMA (Autoregressive Integrated Moving Average Model) Modeling Calculation stochastic error component

And by computes performance index η at random _s:

${\mathrm{\η}}_s=1-{\mathrm{\δ}}_{\mathrm{esmv}}^2/{\mathrm{\δ}}_{\mathrm{es}}---\left(15\right)$

Wherein:

η _sBe performance index at random;

is minimum variance;

δ _EsMinimum variance for the stochastic error component.

In like manner, calculate the determinacy error component of tracking error:

$\mathrm{ed}\left(i\right)=\left\{\begin{array}{cc}{y}_{\mathrm{sp}}\left(i\right)-y\left(0\right)& i＜d\\ y_{\mathrm{sp}}\left(i\right)-y_2^{\′}(i-d+1)& i\≥d\end{array}\right.---\left(16\right)$

Wherein:

Ed (i) is the determinacy error component of error;

y _Sp(i) be the setting value of controlled volume.

Come the determinacy performance of evaluation system through this index of average of error sum of squares with the ascertainment error component:

${\mathrm{\η}}_d=\underset{i=0}{\overset{d-1}{\mathrm{\Σ}}}\mathrm{ed}{\left(i\right)}^2/\underset{i=0}{\overset{\∞}{\mathrm{\Σ}}}\mathrm{ed}{\left(i\right)}^2---\left(17\right)$

Wherein:

η _dBe the determinacy performance index.

As shown in Figure 2, the real time data extraction module is through the trend of segmentation least square linear fit system. and segmentation therein realizes through two threshold values setting up SSE.The exceptional value array of passing through of exceptional value is come buffer memory.

Fig. 3 has provided the algorithm flow that postpones real-time estimation module in the utility model.At first, suppose that the estimation of last step delay is to be listed as accurately to write input vector, use real-time least-squares algorithm then and estimate image parameter.Use current probability density function and confirm that the optimizing that postpones is regional, the minimize losses Function Estimation postpones in this zone, uses this estimated value then and upgrades probability density function, calculates current delay through the probability density function that upgrades.

Fig. 4 has provided the step of the performance evaluation module of system.After extracting trend term, error is decomposed, obtain the randomness error component and the ascertainment error component of error through data processing.Randomness component computing system through error is performance index at random, the determinacy performance index of the determinacy component computing system through error.

The utility model can well the mode through software and configuration be realized in industrial control system with concrete technology to the whole thinking of the real time monitoring of the control system performance of the proposition of the actual demand in the industrial control process.The real-time computing technique of the utility model can realize the calculated off-line and the real time monitoring of system performance.Off-line performance evaluation mainly is to read historical data analysis through real time monitoring software.The real-time performance of control system is kept watch on through reading sampled data in real time and is calculated in real time then and on man-machine interface, show.

The above; Be merely the preferable embodiment of the utility model; But the protection domain of the utility model is not limited thereto; Any technician who is familiar with the present technique field is in the technical scope that the utility model discloses, and the variation that can expect easily or replacement all should be encompassed within the protection domain of the utility model.Therefore, the protection domain of the utility model should be as the criterion with the protection domain of claim.

Claims (1)

1. a control loop performance real time monitoring device is characterized in that this device comprises data acquisition module, pre-processing module, real-time tendency extraction module, real-time status discrimination module, real time delay estimation module, real-time performance computing module and real time monitoring module;

Said data acquisition module is connected with pre-processing module, real-time tendency extraction module, real time delay estimation module and real-time performance computing module respectively; Pre-processing module is connected with the real time monitoring module; The real-time tendency extraction module is connected with the real-time performance computing module with the real-time status discrimination module respectively; The real-time status discrimination module is connected with the real-time performance computing module; The real time delay estimation module is connected with the real-time performance computing module; The real-time performance computing module is connected with the real time monitoring module;

Said real-time tendency extraction module passes through from real-time data acquisition module reading of data, and the trend of extract real-time service data is as the input of state estimation module and real-time performance computing module;

As input, the current time delay of computing system is used for the performance of computing system to said real-time status discrimination module as the input of control system performance evaluation with real-time running data.

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