RU2310913C1 - Device for determining optimal period of technical maintenance of system - Google Patents

Abstract

FIELD: computer engineering, in particular control devices, possible use in scientific research and engineering, where it is required to determine time frame of technical maintenance of complex system, optimal in terms of readiness criterion, and also time of serviceable condition of each subsystem at system service cycle interval.

SUBSTANCE: device contains time sensor, m devices for computing readiness coefficients (based on number of subsystems included in system being serviced), where each evaluator includes a functional transformer, two multipliers, two adders, a subtracter, integrator and divider. Device also includes delay block, which includes m-2 delay elements; analyzer, which realizes selection of the minimal one of m variables, delay element, comparison element, key, block of m output circuits, each one of which represents serially connected delay elements and a key. The device is different from a prototype due to presence of output circuit block, and also second multiplier in each readiness coefficient evaluator.

EFFECT: expanded area of application and expanded information capacity.

1 dwg

Description

The invention relates to control devices and can be used in scientific research and engineering, where it is required to find the periods of technical maintenance of systems that are optimal according to the availability criterion and the uptime of the components of the system. A device [1] is known, which makes it possible to determine a maintenance period that ensures a maximum product availability factor. Its disadvantage is the limited scope, because it focuses on individual products that are not directly part of the system. Also known device [2], designed to determine the optimal period of maintenance of a complex system. Its disadvantage is the narrow scope, since it is not oriented to a system that provides for planned preventive prevention. In addition, this device contains a number of elements that are complex structures. Among them, an adder 10, in which addition and subtraction operations should be simultaneously performed; functional converter 12 implements two functions P (t) and [1-P (t)]. This part of the device is not described clearly enough, there is a typo. The error-free process of choosing the minimum of m variables from the analyzer 11 is problematic because the delay of the output signals of the calculators K _Гj from 9-3 to 9-m, necessary for the implementation of the algorithm of this analyzer, is not visible.

The closest in technical essence to the claimed is a device [3], containing a time sensor, an analyzer that selects the minimum of m variables, delay elements, keys, a comparison element, a registrar, as well as m calculators of subsystem availability coefficients, each of which includes functional converter that implements the function P _j (T), integrator, three adders, divider and multiplier. Its disadvantage is the limited scope, because it does not allow to take into account the time spent on planned preventive maintenance used for a wide class of products and long-term operation systems.

The purpose of the proposed technical solution is to expand the scope and information content of the device. The scope is expanding due to the implementation of a mathematical model that allows you to take into account the residence time of each tool (subsystem) of a complex system in various conditions, including the state of planned preventive prevention. Informative capabilities are expanded by issuing as an output time parameters the operational state of each subsystem at the interval of the system maintenance cycle.

The maintenance process is cyclical. The average duration of the service cycle of any of the subsystems is expressed by the following relation:

where T is the service period;

- среднее время контроля работоспособности;

- average time for monitoring performance;

- среднее время плановой предупредительной профилактики;

- the average time of planned preventive prevention;

- среднее время аварийно-восстановительных работ.

- the average time for emergency repairs.

P (T) is the probability of uptime during T.

If the monitoring of operability and maintenance of the system is carried out in scheduled sessions with a frequency of T, then in the time interval between sessions each subsystem can be not only in a healthy state, but also in a state of latent failure. In this regard, the following relation holds:

- среднее время работоспособного состояния, а

- среднее время пребывания средства в отказе.Where

- the average working time, and

- the average time spent by the means in denial.

определяется по формуле:Value

determined by the formula:

When conducting control, preventive maintenance and emergency recovery operations, as well as when any means of the system is in a state of failure, it cannot function as intended.

It is advisable to carry out maintenance on time, ensuring the required quality of functioning of each tool and the system as a whole. A comprehensive indicator of quality is the availability factor, which is expressed by the following ratio:

Using relations (1), (2), (3), we obtain:

Studies have shown that the function K _G (T) has a single extremum. At a certain value of T *, the availability factor has a maximum value.

образует такую временную программу обслуживания системы, практическая реализация которой может оказаться неприемлемой. Конструктивным решением является применение минимаксной стратегии обслуживания. При этом все подсистемы сложной системы будут обслуживаться одновременно с периодичностью, определяемой следующим образом:The technical system includes many {m} of various complexity and reliability tools. Each tool is characterized by individual values of all components of the service cycle (1). Therefore, for each i-th system tool, it is possible to determine the optimal value T _i * of the maintenance period. The set of values of T _i *,

forms such a temporary system maintenance program, the practical implementation of which may be unacceptable. A constructive solution is to apply a minimax service strategy. In this case, all subsystems of a complex system will be serviced simultaneously with a frequency determined as follows:

or

The proposed model can be implemented in hardware using the proposed device, a diagram of which is shown in the drawing.

), анализатор 11, реализующий выбор минимальной из m переменных (например, блок 13 устройства [3]), элемент задержки 12, элемент сравнения 13, ключ 14, блок из m выходных цепей 15, при этом каждая цепь блока представляет собой последовательно соединенные элемент задержки 16_i и ключ 17_i (

).The device contains a time sensor 1, which determines in ascending order with a step ΔT the possible values of the monitoring and maintenance period of the system, m calculators of subsystem availability coefficients (according to the number of subsystems included in the serviced system). Each calculator contains a functional converter 2 that implements the function P _i (T), the first 6 and second 3 multipliers, the first 4 and second 7 adders, a subtractor 5, an integrator 8 and a divider 9. The device also includes a delay unit 10, including m -2 delay elements 10 _s , (

), an analyzer 11 that implements the choice of the minimum of m variables (for example, unit 13 of the device [3]), a delay element 12, a comparison element 13, a key 14, a block of m output circuits 15, each block circuit is a series-connected element delays 16 _i and key 17 _i (

)

на второй вход, соединенный с первым входом первого сумматора 4, поступает значение

на третий вход, связанный с первым входом первого умножителя 3, подается значений

на четвертый вход, связанный с первым входом функционального преобразователя 2, подается значение λ; пятый вход вычислителя связан со вторыми входами функционального преобразователя 2 и второго сумматора 7, а также с выходом датчика времени 1.Each availability factor calculator has 5 inputs. Before starting the operation of the device, they are fed with the initial values necessary to solve the problem. In this case, the first input connected to the first inputs of the subtractor 5 and the second multiplier 6 receives the value

the second input connected to the first input of the first adder 4 receives the value

to the third input associated with the first input of the first multiplier 3, the values

the fourth input associated with the first input of the functional Converter 2, the value λ; the fifth input of the calculator is connected with the second inputs of the functional Converter 2 and the second adder 7, as well as with the output of the time sensor 1.

The device operates as follows.

The time sensor 1 in increments of ΔT sets in increasing order the sequence of possible values T _j of the monitoring and maintenance period of a complex system T _j = T _j-1 + ΔT, j = 1, 2, .... The signal corresponding to T _j from the first output the time sensor 1 is fed to the second inputs of the second adders 7 and functional converters 2 calculators of the availability factors of the subsystems. In each such calculator, the availability coefficient K _{Гj of the} corresponding subsystem is calculated for each next value of T _j .

We will consider the process of calculating the availability coefficient of a subsystem using the example of one calculator.

соответствующий среднему времени полезного функционирования подсистемы

на периоде T_j, с выхода интегратора 8 передается в делитель 9 и на второй выход вычислителя. Во втором умножителе 3 перемножаются значения величин Р(T_j) и

результат передается в первый сумматор 4.For each next value of T _j in the functional converter 2, the function P (T _j ) = exp {-λT _j } is formed - the probability of failure-free operation of the subsystem and is transmitted to the multipliers 3, 6 and to the integrator 8. In the latter, the function P (T _j ) is integrated and the upper limit of integration is determined by the current value of T _j . Integration Result

corresponding to the average time of the useful functioning of the subsystem

on the period T _j , from the output of the integrator 8 is transmitted to the divider 9 and to the second output of the calculator. In the second multiplier 3, the values of P (T _j ) and

the result is transmitted to the first adder 4.

. Результат перемножения

с выхода первого умножителя 6 передается в вычитатель 5, где вычисляется разность

и передается в первый сумматор 4. Сигнал, соответствующий сумме

с выхода сумматора 4 поступает на первый вход второго сумматора 7. Результат сложения

полученный во втором сумматоре 7, передается в делитель 9, где формируется величина коэффициента готовности подсистемы, соответствующая текущему значению периода контроля и технического обслуживания T_j, т.е.At the same time, in the first multiplier 6, the quantity P (T _j ) is multiplied with the value

. Multiplication result

from the output of the first multiplier 6 is transmitted to the subtractor 5, where the difference is calculated

and transmitted to the first adder 4. The signal corresponding to the sum

from the output of the adder 4 goes to the first input of the second adder 7. The result of addition

obtained in the second adder 7, is transmitted to the divider 9, where the value of the subsystem availability coefficient corresponding to the current value of the monitoring and maintenance period T _{j is formed} , i.e.

The calculated value of K _G (T _j ) from the output of the divider 9 is transmitted to 1 output of the calculator of the coefficient of availability of the subsystem. Thus, for each value of T _j , the signal K _ГJ appears at the 1 output of each calculator, and the signal corresponding to the calculated value of T _Фj appears at the second output. From the first outputs of the first and second calculators of subsystem availability coefficients directly, and from the third to the last similar calculators through the corresponding delay elements of group 10, the calculated values of K _Fji are transmitted to the corresponding inputs of the comparison elements of the analyzer 11 [3]. In this case, the time delay that the delay elements of group 10 must provide is determined by the propagation time of the signals in the circuits of the analyzer 11.

From the output of the analyzer 11 the lowest value of the availability factor

enters the input of the first delay element 12 and the first input of the comparison unit 13. In this case, the previously calculated value

from the output of the delay element 12 is supplied to the second input of the comparison unit 13.

In the initial state, before starting the operation of the device, the delay element 12 is converted to the zero state.

со второго выхода каждого вычислителя коэффициента готовности (

) через соответствующую пару соединенных последовательно элемента задержки 16_i и ключа 17_i, блока выходных цепей 15 поступит на определенный (i) выход устройства.In the comparison element 13, the quantities K _Gj and K _{Gj-1 are} compared with each other, one of which corresponds to the current value of T _J , and the other to the previous T _J-1 . If, as a result of the comparison, it turns out that K _Гj-1 ≤K _Гj , then from the first output of the comparison unit 13 a control signal is issued to the time sensor 1 to output the next value T _{J + 1} and the process of calculating the K _G system will be repeated, but already with a new T _{J +1} period value. Otherwise, i.e. when К _Гj-1 > К _Гj , the control signal from the second output of the comparison unit 13 is supplied to the enable input of the key 14 and the value T _J-1 corresponding to the optimal period of monitoring and maintenance T * of the complex system, from the second output of the time sensor 1 through the key 14 goes to m + 1 output of the device. At the same time, the control signal from the second output of the comparison unit 13 is fed to the enable inputs of the keys 17 _i of the output circuit block 15. In this case, the signal

from the second output of each availability factor calculator (

) through the corresponding pair of series-connected delay element 16 _i and key 17 _i , the block of output circuits 15 will go to a specific (i) output of the device.

соответствующих подсистем. На этом работа устройства заканчивается.Thus, at m + 1 the output of the device will be the value T *, and at the outputs of the block of output circuits, the values

corresponding subsystems. This completes the operation of the device.

The positive effect that the proposed technical solution provides is that the device allows you to determine the optimal period of system maintenance according to the availability criterion, taking into account the time spent on monitoring the condition, scheduled maintenance and repair work of each of the subsystems of the serviced system. In addition, it provides the calculation of the uptime of subsystems with optimal service life of the system as a whole.

Information sources.

1. V.D. Grishin, Yu.S. Manuilov, A.N. Schenev. Patent No. 2228541, M. Cl. ⁷ G07C 3/08, 2004

2. G.N. Vorobyov, D.V. Grishin, A.N. Timofeev. A.S. USSR No. 1679512, M. Cl. ⁵ G07C 3/02, 1991

3. G.N. Vorobyov, D.V. Grishin, D.I. Markov. A.S. USSR No. 1437888, M. Cl. ⁴ G07C 3/02, 1988

4. I.M.Tetelbaum, Yu.R. Schreider. "400 circuits for AVM." - M .: Energy, 1978

Claims (1)

A device for determining an optimal system maintenance period, comprising a time sensor, m calculators of subsystem availability coefficients, each of which contains a subtractor, the second input of which is connected to the output of the first multiplier, and the first input, together with the first input of the first multiplier, is the first input of the availability coefficient calculator, the second input of which is connected to the first input of the first adder, the output of which is connected to the first input of the second adder, the output of which is connected to the second input m divider, the output of which is the first output of the availability factor calculator, and the first input is connected through the integrator to the second input of the first multiplier and the output of the functional converter, the second input of which is connected through the fifth input of the availability factor calculator to the first output of the time sensor, the second output of which is connected to the information input of the key, the output of which is m + 1 the output of the device, and the enable input is connected to the second output of the comparison element, the first output of which is connected to by the time sensor, the first input is directly, and the second input through the delay element is connected to the analyzer output on m inputs, the first input of which is connected directly to the first output of the first availability factor calculator, the second input - directly to the first output of the second availability factor calculator, and the inputs from third in m - through the individual delay elements of the delay block are connected, respectively, with the first outputs of the remaining m-2 calculators of subsystem availability coefficients, characterized in that a block of output circuits is introduced, and a second multiplier is included in each readiness factor calculator, the fourth input of the readiness factor calculator being the first input of the functional converter, the second input of which is connected to the second input of the second adder, and the output is connected to the second input of the second multiplier, the first input of which is the third input of the availability factor calculator, and the output is connected to the second input of the first adder, the third input of which is connected to the output of the subtractor, the outputs integrators are the second outputs of the readiness factor calculators and are individually connected to the corresponding inputs of the output circuit block, which includes m circuits by the number of readiness coefficient calculators, each of which consists of a delay element and a key connected in series, while the resolving key inputs of the output circuit block are parallelized and connected to the second output of the comparison element, the outputs are the corresponding m outputs of the device, and the information inputs through the delay elements soy ineny individually with the respective entrances block m output circuits.