RU2461861C1 - Method of searching for faulty module in continuous dynamic system - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: reaction of a good system is pre-recorded on an interval of control points, and integral estimates of output signals of the system are determined; the system with nominal characteristics is replaced with the inspected system; a similar test signal is fed to the input of the system; integral estimates of signals of the inspected system for control points for the integration parameter are determined; deviation of the integral estimates of signals of the inspected system for control points from nominal values is determined; the signs of the deviation values of integral estimates of signals of the inspected system for control points from nominal values are determined; an operation is performed for pair-wise comparison of elements of the vector of topological connections of the module and the vector of the signs of deviations of integral estimates using a formula; binary diagnostic features are calculated from the relationship and the defective structural unit is determined from the unit value of the binary diagnostic feature.

EFFECT: reduced hardware and computational expenses associated with calculation of diagnostic features of presence of defects.

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Description

The invention relates to the field of monitoring and diagnosing automatic control systems and their elements.

There is a method of finding a faulty unit in a dynamic system (Positive decision dated July 12, 2010 on the grant of a patent for an invention according to application No. 2009123999/08 (033242), MKI 6 G05B 23/02, 2010), based on trial deviations of the transfer function parameters of the model .

The disadvantage of this method is that it uses several models with trial deviations of the parameters of the transfer functions of the blocks.

The closest technical solution (prototype) is a method for finding a faulty unit in a continuous dynamic system (Positive decision of July 22, 2011 on the grant of a patent for an invention according to application No. 2011100409/08 (000540), MKI ⁶ G05B 23/02, 2011).

The disadvantage of this method is that it involves the use of complex diagnostic signs of a defect in the structural unit of the system.

The technical problem to which this invention is directed is to reduce the hardware and computing costs associated with the implementation of the calculation of diagnostic signs of a defect.

, путем подачи на первые входы k блоков перемножения сигналов системы управления, на вторые входы блоков перемножения подают экспоненциальный сигнал e^-αt, выходные сигналы k блоков перемножения подают на входы k блоков интегрирования, интегрирование завершают в момент времени Т_к, полученные в результате интегрирования оценки выходных сигналов F_{j ном}(α), j=1, 2,…, k регистрируют, фиксируют число m блоков системы, определяют элементы топологических связей каждого блока, входящего в состав системы для каждой контрольной точки P_ji, j=1, 2,…, k; i=1, 2,…, m, элементы P_ji определяют из множества значений {-1, 0, 1}, значение -1 определяют, если знак передачи сигнала от выхода i-го блока до j-й контрольной точки отрицательный, значение 0 определяют, если передача сигнала от выхода i-го блока до j-й контрольной точки отсутствует, значение 1 определяют, если знак передачи сигнала от выхода i-го блока до j-й контрольной точки положительный.The task is achieved by pre-registering the reaction of a known-good system f _{j nom} (t), j = 1, 2, ..., k on the interval t∈ [0, T _K ] at κ control points, and determine the integral estimates of the output signals F _{j nom} (α), j = 1, 2, ..., k of the system, for which, at the time the test signal is input to the input of the system with nominal characteristics, the integration of the control system signals at each of the k control points with weights e ^-αt starts at the same time, where

, by applying the control system signals to the first inputs k of the multiplication blocks, the exponential signal e ^{-αt is} supplied to the second inputs of the multiplication blocks, the output signals of the multiplication blocks are fed to the inputs of the integration blocks k, the integration is completed at time T _to , obtained as a result of integration of the estimate output signals F _{j nom} (α), j = 1, 2, ..., k, register, fix the number m of system blocks, determine the elements of topological links of each block included in the system for each control point P _ji , j = 1, 2, ..., k; i = 1, 2, ..., m, elements P _{ji are} determined from the set of values {-1, 0, 1}, a value of -1 is determined if the sign of signal transmission from the output of the i-th block to the j-th control point is negative, the value 0 determine if the signal transmission from the output of the i-th block to the j-th control point is absent, the value 1 is determined if the sign of the signal transmission from the output of the i-th block to the j-th control point is positive.

Then, the system with the nominal characteristics of the controlled system is replaced, a similar test signal x (t) is supplied to the input of the system, the integrated estimates of the signals of the controlled system are determined for k control points F _j (α), j = 1, 2, ..., k for the integration parameter α, determine the deviations of the integral estimates of the signals of the controlled system for k control points from the nominal values ΔF _j (α) = F _j (α) -F _{j nom} (α), j = 1, 2, ..., k.

The signs of deviations of the integrated estimates of the signals of the controlled system for k control points from the nominal values of sign (ΔF _j (α)), j = 1, 2, ..., k are determined.

Then, the operation of pairwise comparison of the elements of the vector of topological connections of the i-th block P _ji , j = 1, 2, ..., k; i = 1, 2, ..., m and the vector of signs of the deviations of the integral estimates sign (ΔF _j (α)), j = 1, 2, ..., k according to the formula:

Since the operation ≡ is an equivalence operation, expression (1) takes the value 1 only if all elements of the vectors P _ji , j = 1, 2, ..., k and sign (ΔF _j (α)), j = 1, 2, ..., k for each control point are pairwise equal.

Then, the operation of pairwise comparison of the inversion elements of the vector of topological connections of the i-th block inν (P _ji ), j = 1, 2, ..., k; i = 1, 2, ..., m and the vector of signs of deviations of the integral estimates sign (ΔF _j (α)), j = 1, 2, ..., k according to the formula:

Since the operation ≡ is an equivalence operation, expression (2) takes the value 1 only if all elements of the vectors inν (P _ji ), j = 1, 2, ..., k and sign (ΔF _j (α)), j = 1, 2, ..., k for each control point are pairwise equal.

Then produce the calculation of binary diagnostic features from the ratio:

The first term of formula (3) takes the value 1 if the signs of the deviations of the integral signal estimates coincide with the elements of the topological relationship vector, the second term of the formula (3) takes the value 1 if the signs of the deviations of the integral signal estimates coincide with the inverted elements of the topological connection vector. The inversion of the vector of topological relationships takes into account the possibility of a defect in the same block both with a plus sign (for example, an increase in the value of a block parameter) and with a minus sign (for example, a decrease in the value of a block parameter).

The unit value of the binary diagnostic feature determines the structural unit with a defect.

Thus, the proposed method for finding a faulty unit is reduced to performing the following operations:

1. As a dynamic system, consider a system consisting of arbitrarily connected m dynamic blocks.

2. Pre-determine the control time T _To ≥T _PP , where T _PP - the transition process of the system. The transient time is estimated for the nominal values of the parameters of the dynamic system.

.3. Determine the parameter of the integral signal conversion from the ratio

.

4. Fix the number of control points k.

5. Pre-determine the elements of topological connections of each block included in the system for each control point P _ji , j = 1, 2, ..., k; i = 1, 2, ..., m, elements P _{ji are} determined from the set of values {-1,0,1}, a value of -1 is determined if the sign of signal transmission from the output of the i-th block to the j-th control point is negative, the value 0 determine if the signal transmission from the output of the i-th block to the j-th control point is absent, the value 1 is determined if the sign of the signal transmission from the output of the i-th block to the j-th control point is positive.

6. A test signal x (t) (unit step, linearly increasing, rectangular pulse, etc.) is supplied to the input of a control system with nominal characteristics. The proposed method does not provide fundamental restrictions on the type of input test exposure.

7. The reaction of the system f _{j nom} (t), j = 1, 2, ..., k on the interval t∈ [0, T _K ] is recorded at κ control points and the integral estimates of the output signals are determined

, для чего сигналы системы управления подают на первые входы k блоков перемножения, на вторые входы блоков перемножения подают экспоненциальный сигнал e^-αt, выходные сигналы k блоков перемножения подают на входы k блоков интегрирования, интегрирование завершают в момент времени Т_к, полученные в результате интегрирования оценки выходных сигналов F_{j ном}(α), j=1, 2,…, k регистрируют.F _jnom (α), j = 1, 2, ..., k of the system. For this, at the moment of supplying the test signal to the input of the control system with nominal characteristics, the integration of the control system signals at each of k control points with weights e ^{-αt starts}

why the control system signals are fed to the first inputs of the multiplying units, the exponential signal e ^{-αt is} supplied to the second inputs of the multiplying units, the output signals of the multiplying units are fed to the inputs of the integration blocks k, the integration is completed at time T _to , obtained as a result of integration estimates of the output signals F _{j nom} (α), j = 1, 2, ..., k are recorded.

8. Replace the system with the rated characteristics controlled. A similar test signal x (t) is supplied to the system input.

9. Determine the integral estimates of the signals of the controlled system for k control points F _j (α), j = 1, 2, ..., k, performing the operations described in paragraphs 6 and 7 in relation to the controlled system.

10. The deviations of the integral estimates of the signals of the controlled system for k control points from the nominal values ΔF _j (α) = F _j (α) -F _{j nom} (α), j = 1, 2, ..., k are determined.

11. Determine the signs of deviations of the integrated estimates of the signals of the controlled system for κ control points from the nominal values of sign (ΔF _j (α)), j = 1, 2, ..., k.

12. Perform the operation of pairwise comparison of the elements of the vector of topological connections of the i-th block P _ji , j = 1, 2, ..., k; i = 1, 2, ..., m and the vector of signs of the deviations of the integral estimates sign (ΔF _j (α)), j = 1, 2, ..., k according to the formula:

13. Perform the operation of pairwise comparison of the inversion elements of the vector of topological connections of the i-th block inν (P _ji ), j = 1, 2, ..., k; i = 1, 2, ..., m and the vector of signs of the deviations of the integral estimates sign (ΔF _j (α)), j = 1, 2, ..., k according to the formula:

14. The calculation of binary diagnostic features from the ratio:

15. The unit value of the binary diagnostic feature determines the structural unit with a defect.

Consider the implementation of the proposed method for finding a defect for a system whose structural diagram is shown in the drawing.

Transfer functions of blocks:

;

;

,

;

;

,

nominal values of the parameters: K ₁ = 1; T ₁ = 5 s; K ₂ = 1; T ₂ = 1 s; K ₃ = 1; T ₃ = 5 s.

Define the elements of topological connections of each block included in the system for each control point P _ji , j = 1, 2, 3; i = 1, 2, 3, the sign of signal transmission from the output of the first block to the first control point is positive, therefore P ₁₁ = 1, the sign of signal transmission from the output of the first block to the second control point is positive, therefore P ₂₁ = 1, the sign of signal transmission from the output of the first block to the third control point is positive, therefore P ₃₁ = 1, so the topological link vector of the first block will look like: P ₁ = (1,1,1). For the second block, the sign of signal transmission from its output to the first control point is negative, and for the second and third control points it is positive, therefore the vector of topological links for the second block will have the form: P ₂ = (- 1,1,1). For the third block, the vector of topological connections will have the form: P ₃ = (- 1, -1,1).

When searching for a single defect in the form of a deviation of the time constant T ₁ = 4 s (defect No. 1) in the first link by supplying a step test input signal of unit amplitude and integral signal estimates for the parameter α = 0.5 and T _to = 10 s, the values of binary diagnostic signs are obtained the presence of a defect according to formula (3) when using three control points located at the outputs of the blocks. The defect calculated by the formula (3) gives the following values of binary diagnostic features: J ₁ = 1; J ₂ = 0; J ₃ = 0.

Simulation of defects search processes in the second and third blocks for a given diagnostic object with the same integration parameter α and with a single step input signal gives the following values of binary pointers:

If there is a defect in block No. 2 (in the form of a decrease in the parameter T ₂ by 20%, defect No. 2): J ₁ = 0; J ₂ = 1; J ₃ = 0.

If there is a defect in block No. 3 (in the form of a decrease in the parameter T ₃ by 20%, defect No. 3): J ₁ = 0; J ₂ = 0; J ₃ = 1.

The single value of the binary diagnostic feature in all cases correctly determines the defective block.

Claims (1)

A method for finding a faulty block in a continuous dynamic system, based on the fact that the number of blocks m that are part of the system is fixed, the monitoring time T _K ≥Т _{ПП is} determined, where Т _ПП is the transient time of the system, the integral signal conversion parameter is determined from the relation

use a test signal on the interval t∈ [0, T _K ], use the integral signal estimates obtained for real values of the Laplace variable as the dynamic characteristics of the system, fix the number k of control points of the system, record the reaction of the diagnostic object and the reaction of a known good system f _{j nom} (t), j = 1, 2, ..., k on the interval t∈ [0, T _K ] at k control points, determine the integral estimates of the output signals F _{j nom} (α), j = 1, ..., k of a working system , for which at the time of the test signal at the input of the system with characteristics and simultaneously start the integration control system signals in each of the control points k with weights e ^-αt, wherein

by applying the control system signals to the first inputs k of the multiplication units, the exponential signal e ^{-αt is} supplied to the second inputs of the multiplying units, the output signals of the multiplying units are fed to the inputs of the integration blocks k, the integration is completed at time T _K , obtained by integrating the output estimates signals F _{j nom} (α), j = 1, ..., k are recorded, replace the system with the nominal characteristics of the controlled, the input of the system serves a similar test signal x (t), determine the integral estimates of the signals of the control of the system being monitored for k control points F _j (α), j = 1, ..., k for parameter α, the deviations of the integral estimates of the signals of the controlled system for k control points from the nominal values ΔF _j (α) = F _j (α) -F _{j nom} (α), j = 1, ..., k, determine the elements of topological connections of each block included in the system for each control point P _ji , j = 1, ..., k; i = 1, ..., m, elements P _{ji are} determined from the set of values {-1,0,1}, a value of -1 is determined if the sign of signal transmission from the output of the i-th block to the j-th control point is negative, the value 0 is determined if there is no signal transmission from the output of the i-th block to the j-th control point, the value 1 is determined if the sign of the signal transmission from the output of the i-th block to the j-th control point is positive, characterized in that the signs of deviations of the integral signal estimates are determined controlled system for k control points from the nominal values of sign ((ΔF _j (α)), j = 1, 2, ... , k, perform the operation of pairwise comparison of the elements of the vector of topological connections of the i-th block P _ji , j = 1, 2, ..., k; i = 1, 2, ..., m and the sign vector of the deviations of the integral estimates sign ((ΔF _j (α )), j = 1, 2, ..., k by the formula:

perform the operation of pairwise comparison of the inversion elements of the vector of topological connections of the i-th block inν (P _ji ), j = 1, 2, ..., k; i = 1, 2, ..., m and the vector of signs of deviations of the integral estimates sign ((ΔF _j (α)), j = 1, 2, ..., k no by the formula:

calculate binary diagnostic features from the ratio:

the unit value of the binary diagnostic feature determines the structural unit with a defect.