SU1767510A1 - Device for determining article optimum maintenance cycle - Google Patents

Abstract

The invention relates to computing, in particular, to control devices, and can be used in scientific research and engineering, where it is required to determine the optimal period for maintenance and the probability of reliable operation of a product on a limited resource (given the active product operation time. The device includes a time sensor 1, a nonlinearity unit 2, an amplifier 3, an integrator 4, blocks 5 and 9 divisions, comparators 6 and 19, memory elements 7, 10, 11, 21 and 22, keys 8, 12, and 15, adder 13, multiplication unit 14, trigger 16, linearly varying voltage generator 17, multivibrator 18, And 20 element differentiating element 22 and inverter 24. 1 Il.

Description

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The invention relates to computer technology, in particular, to control devices, and can be used in scientific research and technology, where it is necessary to determine the optimal period of maintenance and the probability of reliable operation of a product on a limited resource.

A technical solution is known that includes a time sensor, a nonlinear conversion unit, an integrator, two dividing units, three comparators, seven switches, three delay elements, a counter, three memory elements, a memory block, a recorder, three multipliers and three adders 1. It allows you to determine the optimal period of system maintenance, operating with a availability factor not lower than the specified one. However, it does not take into account the change in the reliability characteristics of the product during operation, does not allow to determine the probability of a product to fail without fail over a specified time, and has a low speed.

The closest in technical essence to the invention is a technical solution comprising a timer, a nonlinearity unit, an integrator, three delay elements, a comparator, three memory elements, a one-shot, three keys, two division blocks, four multiplication units and three adders 2, It defines It is the optimal period of maintenance according to the criterion of the minimum of unproductive consumption of a resource, which comes in per unit time of the useful functioning of the product.

The disadvantage of it is that it does not allow to determine the optimal period of maintenance of the product, operating with a availability factor not lower than the specified one, taking into account changes in the reliable characteristics of the product during operation, and does not determine the probability of trouble-free operation of the product over a specified time.

The aim of the invention is to expand the field of application of the device by determining the availability factor not lower than the specified value, taking into account changes in the reliability characteristics of the product during operation and the probability of trouble-free operation of the product for a specified time.

During operation, the product is subjected to maintenance (TO) in order to maintain them in working condition.

One of the main quantitative characteristics of a TO is a service period, the value of which is advisable to find in view of the required readiness of the product for its intended use.

The most important characteristic of the availability of a product is the availability factor, which in general can be determined by the formula

k-tf

Cg-tg

0)

where Tc is the specified time of operation of the product;

Tf is the average operating time of the product on the Tc interval.

For many products, it is characteristic that failures occurring in them are detected and eliminated during maintenance. The condition of the product as a result of the maintenance is updated.

The availability factor value essentially depends on the maintenance period and on the failure rate. There is a wide class of products with increasing function I (t) of failure rate. Besides,

the service time of the product depends on the period of maintenance. An increase in the time interval between maintenance deteriorates the state of the product, the untimely elimination of some failures may lead to the appearance of new failures, which requires an increase in the time of diagnostic control and restoration of the product's operability.

In this connection, the change in availability factor Kg will be considered in terms of changes in both the failure rate A and the period g of service of the product. Studies show that the function Kg (Yt) is a monotonically decreasing function. For such products, the period of maintenance is taken to be based on the required KgzaA readiness factor, i.e. t (Yag) Ј Kgzad.

For a given time Tc operation (limited resource) of the product

You can write the balance ratio of the following form:

N {Gf + G0 + Gobs} Tc, (2)

Where N is the number of sessions of maintenance on the resource Tc;

Tf is the average operating time of the product for a period of service;

55

H / p (t) dt;

(3)

p (t) exp {- / A (x) dt (4)

there is the probability of a product failing to work;

to is the average time the product has been in a failure state over the interval.

That C - TF

(five)

The average time Tf of the condition of the product during the time Tc will be N Gf. The service time The hobs item is a function of the service period and can be represented by the ratio

Tobs CT,

(6)

where K is the proportionality coefficient. Therefore, expression (1) takes the form

Kg

MTF

/ P (t) dt

N (GF + to + GobsT + KG

The task of finding the period of maintenance, ensuring the functioning of the product with the required readiness, we rewrite in the following form

/ P (t) dt -FTKF- "

In the process of development and operation of the product, the value of such a characteristic as the probability of failure-free operation of the product for a given Tc operation time is important. The value of this probability can be calculated by the formula

P P (r) (9)

in this case, the number of sessions N will be calculated using the relation (2) taking into account the found T of the TO period, i.e.

Tc

+ Ct

.

(ten)

The invention is illustrated in the drawing.

The device comprises a time sensor 1, a nonlinearity unit 2, an amplifier 3, an integrator 4, a first dividing unit 5, a first comparator 6, a first memory element 7, a first key 8, a second dividing unit 9, a second memory element 10, a third memory element 11 ty, second key 12, adder 13, multiplication unit 14, third key 15, trigger 16, linear variable voltage generator (GLINE) 17, multivibrator 18, second comparator 19, element 20, fourth memory element 21, fifth memory element 22, differentiating element 23 and inverter 24.

The device works as follows.

When a start signal is received from the third input of the device, the trigger 16 is switched to a single state. The control single signal from the output of the trigger 16 is fed to the inputs of the second key 12, the nonlinearity unit 2 and the timer 1, and the two are started up simultaneously (synchronously). From the first input of the device to the input of the second dividing unit 9, the value of the parameter Tc flows, from the second input of the device to the input of the nonlinearity unit 2, the value of the parameter x (t), from the fourth input

device to the input of the second key 12 receives a signal equal to one. At the output of block 2 non-linearity, a signal is generated.

T P (t) exp (- / (x) dx, which is fed to the input

°

the third element 11 of the memory in the input of the integrator 4, from the output of which the value

Tf signal J P (x) dx is fed to the input of the pen

5th division unit. Sensor 1 is a generator of linearly varying voltage, the output of which generates a signal for output (t.) T. This signal is fed to the input of the first element.

7 memory and through the amplifier 3, the gain of the dividing units 9. The value of the signal N (t) Tc / (g + K t) from the output of the second dividing unit 9 is fed to the input of the second memory element 10. Signal value Kg (t)

TF / (g + K g) from the output of the first block 5 division enters the input of the first comparator

6, where it is compared with the setting value Kg. As soon as, at the moment of time to, Kr (t), Kr (to) will become KG3, at the output of the first

the comparator 6 has a VITS signal indicating that the optimum period of maintenance of the product has been found. The signal from the output of the first comparator 6 is fed to the inputs of GLINE 17, the multivibrator 18, the first key 8 and the memory elements 10 and 11. On the front of the control signal from the output of the first comparator 6 in the memory elements

7, 10 and 11, the value of the signal that they had at the input at time point to is remembered. The value of the signal r to corresponding to the period TO, ensuring the functioning of the product with the required readiness, from the output of the first memory element 7 through the public key 8 is fed to

first exit device. The output of the third memory element 11 will be the signal value P (g) P (to), which is fed to the second input of multiplication unit 14. The signal NN (to), corresponding to the number of maintenance sessions on the resource Tc, is output from the output of the second memory element 10 The first input of the second comparator 19. The signal from the output of the first comparator 6 simultaneously switches on multivibrator 18 and CLAY 17, the output of which generates signals of output (t) Lt, where L is a constant coefficient. This signal is fed to the second input of the second comparator 19. In the second comparator 19, two signals N and Lt are compared to each other. While N Lt, the output of the second comparator 19 will be single and the signal that arrives at the first input of the element 20 and through the inverter 24 to the input of the third key 15. The multivibrator 18 generates pulses with a period equal to 1 / L or pulses per unit time . As soon as, at time t, N becomes Lt, the output of the second comparator 19 turns on a zero signal. During the time t from the output of the element AND 20 to the control input of the fourth element 21 of the network and to the input of the differentiating element 23, N pulses will arrive. The calculation of P is carried out as follows. In the fourth memory element 21, a normally closed key (not shown) is used, and a normally open key (not shown) is used in the fifth memory element 22. In the initial state (before the arrival of the first pulse from the output of the AND element 20), the output of the fifth memory element 22 will be a zero signal, the output of the second key 12 and the output of the adder 13 will be a signal equal to one, at the output of the multiplication unit 14 and the output of the fourth memory element 21 will be .signal P (t). The fourth memory element 21 is in the open state, and the fifth memory element 22 is in the closed state. Upon receipt of the first pulse from the output of the element And 20, the following occurs. On the front of this pulse, the fourth memory element 21 is closed, then for some time (determined by the parameters of the differentiating element 23) the fifth memory element 22 is opened and the value P (t) from the output of the fourth memory element 21 is written to the output of the fifth memory element 22 memory According to the signal from the output of differentiating unit 23, the trigger 16 is transferred to the zero state and closes the second key 12. As a result, the output of the adder 13 will be a signal P (t), and the output of the multiplication unit 14 will be

signal P (s). As the pulse decays from the output of the AND element 20, the fourth memory element 21 opens and at its output will be a signal Pfr) 2. The circuit is ready to receive the next pulse from the output of the element 20. The differentiating unit 23 is needed so that the fifth memory element 22 opens slightly later than the fourth memory element 21 closes and closes before

a fourth memory element 21 will open. After a pulse arrives from the output of the element AND 20, the output of the fifth memory element 2 will be the value of the signal P P (z) N and the third key 15 will open with the signal from the first

the inverter 24. As a result, the P value of the product failure probability for a given time Tc from the output of the third key 15 will go to the second output of the device. The operation of the device ends there.

Claims (1)

Invention Formula A device for determining the optimal period for the technical condition of a product, comprising a time sensor, a nonlinearity unit, the output of which is connected to the integrator input, the output of which is connected to the first input of the first division unit, the output of which is connected to the input of the first comparator, the output of the adder is connected to the first input of the multiplication unit, the first inputs of the first key, first, second and third memory elements are combined, the output of the first memory element connected to the second input of the first key, the output of which is the first output the second key and the output of the third key are the second output of the device, characterized in that, in order to expand the field of application of the device, taking into account the availability factor, below the preset, the fourth and fifth memory elements, the differentiating element, the first inverter, the AND element, the second comparator, the generator of the linearly varying voltage, the multivibrator and the trigger, the first input of which is the third input of the device, and the output is connected to the timer input and the first input of the second key, the second input of which is the fourth input of the device, and the output is connected to the first input of the adder, the output of the time sensor is connected to the second input of the first element memory and through the amplifier to the second input of the first dividing unit and the first input of the second dividing unit, the first input of which is the first input of the device, and the output is connected to the second input of the second memory element, the output of which is connected to the first input of the second comparator, the output of which is connected to the input of the inverter, the output of which is connected to the first third key, and with the first input of the element I, the output of which is connected to the first input of the fourth memory element and the input of the differentiating element, the output of which is connected to the second input of the trigger and the first input of the fifth memory element, output which is connected to the second input of the key and the second input of the adder, the second input of the nonlinearity unit is the second input of the device, and the output is connected to the second input 0 The third memory element, the output of which is connected to the second input of the multiplication unit, the output of which is connected to the second input of the fourth memory element, the output of which is connected to the second input of the fifth memory element, the output of the first comparator is connected to the first input of the first key and the generator inputs linearly variable voltage and multivibrator, the outputs of the last two are connected to the second inputs of the second comparator and element I.