RU2358320C2 - Device for determining optimum program for technical servicing system - Google Patents

Abstract

FIELD: physics; computer engineering.

SUBSTANCE: present invention relates to computer engineering. It can be used in scientific research and technology, where there is need to determine the optimum time program for servicing technical equipment making up a single complex or system. This outcome is achieved by that, the device has a memory unit, two multiplier units, three adders, two dividers, a subtractor, non-linearity unit, time sensor, comparator unit, integrator, three delay elements, OR gate, monostable multivibrator, memory element, switch, and a shift register. The device differs from the prototype by presence of a shift register, a second divider, second multiplier unit and a range of new inter-unit connections.

EFFECT: more functional capabilities and wider field of application.

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Description

The invention relates to modeling devices (may relate to control devices). It can be used in scientific research and operational practice to determine the optimal terms for servicing the means of technical complexes and systems.

There are a number of works, including [1, 2, 3], which discuss various strategies for the maintenance of products and systems. The approaches proposed in them are not brought to the algorithms and devices that ensure their practical application without corresponding modifications.

A device is known [4], designed to determine the optimal criterion of minimum downtime for the period of maintenance of the product. Its disadvantage is a narrow scope, limited to products that are not directly part of a complex system. In addition, it is focused on products with an instant manifestation of failures when they occur.

Devices are also known [5, 6], which provide the determination of the optimal service period of a complex system by implementing the minimax criterion. Moreover, all subsystems that are part of a complex system must be serviced with the same frequency, corresponding to the optimal period of the most unreliable subsystem. It is advisable to use these devices for systems whose subsystems are close in reliability. If the subsystems significantly differ in reliability, then servicing them with the same frequency calculated by the devices [5, 6] will not allow rational use of the reliability potential of other, more reliable systems.

In conclusion, we note that in these devices the readiness coefficient is adopted as an indicator of the quality of the system's functioning. They do not provide a determination of the optimal terms of service when using other indicators, including the downtime coefficient. Thus, we can conclude that the devices [5, 6] have a limited scope.

The closest in technical essence to the claimed invention is a device [7], containing five adders, a multiplication unit, a nonlinearity unit, four memory elements, an integrator, two timers, a division unit, three delay elements, two triggers, an OR element, two comparators and three the key.

The disadvantages of the device are limited functionality and scope, as it focuses on isolated products that are not directly part of a complex system, and is not intended to determine temporary maintenance programs.

The purpose of the claimed technical solution is to expand the functionality and scope of the device. The goal is achieved by implementing a mathematical model that allows you to define a temporary system maintenance program that provides the optimal frequency of service for each of the subsystems and the system as a whole.

The system, as you know, includes a set of means (elements) that are in relationships and relationships with each other, forming a certain integrity, unity. An example of a technical system is an air traffic control system. Its functional elements are: a radio engineering complex, data transmission equipment, an information-computer complex, a complex of information display facilities, and others. Quantitative indicators of reliability and maintainability of the system tools are different, therefore, the optimal terms for their maintenance are different. Determining the optimal programs for such systems is an urgent task.

The process of servicing hardware is cyclical in nature. The average duration of the maintenance cycle of each system tool is expressed by the following ratio:

where τ is the service period;

τ _to - the average duration of state monitoring;

τ _p - the average duration of preventive prevention;

τ _in - the average duration of emergency recovery work;

P (τ) - the probability of failure of the tool on the period τ.

We believe that the actual state of the funds is revealed in the scheduled control sessions. In this regard, the following relation holds:

where τ _f - the average time of a healthy state;

τ _about - the average time spent in failure by the period τ.

The working time of the product during the maintenance period is determined as follows:

With the exponential law of time distribution, the occurrence of failures is valid for the following relation:

P (τ) = exp {-λτ},

where λ is the failure rate of the facility.

The organization of the operation of the means provides for the determination of rational or, in a sense, optimal terms of maintenance, ensuring the required quality of functioning of these means.

An important indicator of the quality of functioning is the idle rate. Its value can be calculated using the relation:

The analysis of the function To _p (τ) (figure 1) shows that there is a maintenance period at which the downtime coefficient reaches a minimum value

To _p *. The task of determining the optimal period for servicing the funds is written as follows:

The considered approach is advisable to use in relation to individual, functionally separate means. However, along with such tools, technical complexes have become widely used, which include many different in structure, complexity and reliability of the means. Each of these tools will have its own optimal maintenance period τ * _i . The set of calculated values of τ * _i , corresponding to the set of tools of the complex i = 1, n, can form such a set of service cycles in time that its practical implementation will be irrational or impossible. Therefore, there is a need to streamline this aggregate by finding compromise, close to optimal, values of service periods for all means of the complex. Such a compromise is a reflection of the decisive rule, which is introduced informally and determines the acceptable deviation of the values of the periods of servicing the funds from the optimal τ * _i values. Constructive from the point of view of streamlining the terms of servicing the multi-reliable facilities of the complex is the multiplicity of the periods of their servicing. Different facilities of the complex (or groups of facilities) will be serviced at different intervals:

{τ _p , 2τ _p , ... mτ _p },

where τ _p is the estimated time of the service period of the least reliable means;

m is the number of highly reliable means (groups of means) of the complex.

The beginning of each time interval kτ _p , k = 1, m, will correspond to the beginning of the maintenance cycle of one or more complex facilities close in reliability. A separate facility of the complex S _i will be serviced with a period k _i τ _p sufficiently close to τ * _i .

The decisive rule is to ensure that the multiplicity of the service periods of the complex means τ _i = k _i τ _{p is} ensured and the condition:

Relation (6) reflects the general approach to solving the problem under consideration. However, its particular variant used in the claimed invention is of practical importance, namely

- оптимальный период технического обслуживания наименее надежного средства системы.Where

- The optimal maintenance period for the least reliable system tool.

This condition is transformed into the choice of a certain acceptable value of the idle coefficient K _p ^d which ensures the fulfillment of the minimization requirement (7) and determines the boundaries of the permissible value τ ^d _i of the service period of the facility. The value of τ ^d _i is determined on the basis that the downtime coefficient of each tool will be equal to some acceptable value, that is, K _pi = K _pi ^d .

Figure 1 shows, by way of example, the results of a study of the dependence of K _p (τ) for three differently reliable means and a graphical interpretation of the results of the implementation of relation (7) is given.

Some deviation of K _pi from the minimum K _pi ^* allows you to expand the range of acceptable values τ ^d _i of the service period. The value of K _pi ^d can be defined as some part 0 <µ≤1 of the minimum value, that is, K _pi ^d = µK _pi ^* . Moreover, τ ^d _{i is} not limited only to τ ^* _{i by the} optimal value, but will be in the interval t ^d _ni <τ ^d _i <τ ^d _kon.i , where τ ^d _ni = τ * _i -Δτ _li , τ ^d _kon.i = τ ^* _i + Δτ _2i (Fig. 1). This allows you to identify the specific (computing) values of the periods of service T ^calc _i = τ _i complex means for the operation of these funds with the least possible downtime coefficients K ^calc ≤K _{pi pi} ^d.

Note that the preferred region for solving this problem is the range of values of the period τ _i limited by the optimal value τ ^* _i and the maximum allowable τ ^d _end.i , i.e., τ ^* _i <τ _i ≤τ ^d _end.i. Since the periods of servicing individual funds are determined by the condition of their multiplicity, this ensures rational organizational maintenance of the complex of funds as a whole.

The results of solving the problem in relation to the considered example (the system consists of three tools) can be presented in the form of timelines for servicing the system tools, presented in figure 3,

where T is the frequency of servicing the system as a whole.

From the graphs shown in figure 3 it can be seen that the frequency of maintenance of various system tools is different, while

,

,

- оптимальный период наименее надежного средства системы.Repeat that

- the optimal period of the least reliable means of the system.

The proposed model can be implemented in hardware using the proposed device, a diagram of which is shown in figure 2. The device contains a memory block 1, which receives the initial data, the first 2 and second 17 multiplication blocks, the first 3, second 4 and third 6 adders, a nonlinearity block 5 that implements the function P (t), a time sensor 7, which generates a time value Δτ. The device also contains the first 18, second 12 and third 11 delay elements, a comparison unit 8, the first 9 and second 16 dividing units, a waiting multivibrator 13, an OR 20 circuit, a memory element 14, an integrator 10, a key 15, a shift register 19, providing reading the source data for each subsystem, and the subtractor 21. Note that in the composition of the claimed device, the memory block 1, the time sensor 7, the comparison unit 8, the waiting multivibrator 13, the subtractor 21 are equivalent to the similar prototype blocks, namely: a memory element, timer, comparator, trigger adder What is considered in the claims.

Before starting the operation of the apparatus in the memory unit 1 for charting the initial values: K ^d _pi, λ _i, τ _pi -τ _Bi, τ _{Bi Ki} + _{^{τ, τ * i, τ * min}} , where τ ^* _min - optimal maintenance period the least reliable means of the complex, a τ ^* _i - similar values of the remaining means of this complex. Note that memory block 1 is divided into n zones according to the possible number of subsystems of means of a complex system of the complex.

The device operates as follows.

The signal "Start", coming from the first input of the device, the shift register 19 is reset. The same signal, delayed by the first delay element 18, passing through the OR circuit 20, sets the unit in the first category of the shift register 19, and also starts the time sensor 7. The signal of the shift register 19 reads the values of the input quantities from the memory unit 1 to the functional elements of the device. The time sensor 7 generates a time value Δτ and transfers it to the second input of the third adder 6, the first input of which from the fifth output of the memory unit 1 receives the optimal value of the service period τ ^* _{1 of the} first of the studied subsystems. The result of adding τ ^* ₁ + Δτ from the output of the third adder 6 is transmitted to the second inputs of the second adder 4 and the nonlinearity block 5, and also through the delay element 11 to the memory element 14. The value τ is transmitted to the first input of the second adder 4 from the fourth output of the memory side 1 _k1 + τ _B1 , and from the third output of the memory block 1, the value λ _{1 is} supplied to the first input of the nonlinearity block 5. In the nonlinearity block 5, a signal P (τ ^* _i + Δτ) is generated, which is transmitted to the first input of the integrator 10 and to the second input of the first multiplication block 2. The value τ _p1 -T is received at the first input of the first multiplication block 2 from the second output of memory block 1 _c1 . The signal corresponding to the value _{^{P (τ * i + Δτ)}} (τ _pi -τ _c1), with the output of the first multiplier 2 is transmitted to the first input of the first adder 3. Significance

(τ ^* _i + Δτ) + (τ _k1 + τ _b1 ) from the output of the second adder 4 goes to the second input of the first adder 3, as a result, a signal is generated at its output that corresponds, according to (1), the duration of the service cycle τ _c = P (τ ^* ₁ + Δτ) (τ _{c1 n1} -τ) + (τ ^* ₁ + Δτ) + (τ _k1 + τ _c1), and transmitted to the second input of the first divider 9 and the first input of the subtracter 21. at the same time, integrator 10 calculates the time value:

and transferred to the second input of the subtractor 21.

A signal corresponding to the downtime of the means is generated in the subtractor 21. Its value, taking into account (2), is expressed as follows:

Τ _prost.1 signal from the subtractor is transmitted to the first dividing unit 9 where the calculated value of the coefficient K _n1 layup in accordance with (4) and transmitted to the second input of the comparator 8, to a first input of which the first output of the storage unit 1 is supplied value K _n1 ^d . In the comparator 8, the input quantities are compared with each other. If it appears that the computed value of K _n1 (τ ^* ₁ + Δτ) ≤K ^d _n1, the control signal is generated at the first output 8 of the comparator and transmitted to the timer 7, whereby the time the sensor 7 output signal increased by Δτ, i.e. it will be equal to 2Δτ, and the process of calculating the value of K _n1 repeated, but with the new value of the maintenance period, ie T ₁ = τ ^* ₁ + 2Δτ. Calculating K _n1 cycle will be repeated every m-nym incrementing the period τ ₁ = τ ₁ ^* + mΔτ as long as there is retained the inequality K _n1 ^d _n1 ≤K. As soon as it turns out in comparator 8 that the calculated value K _p1 > K _p1 ^d , a control signal appears on the second output of comparator 8, which starts the waiting multivibrator 13. The control signal, from the output of the multivibrator 13, is fed to the second input of the integrator 10 and resets its value to zero, opens the key 15 and enters the second input of the memory element 14. According to this signal, the calculated value of the service period delayed by the element 11 for one calculation cycle τ _i = τ ₁ ^* + (m-1) Δτ, from the output of the memory element 14 through key 15 goes to the second input the second division block 16. The signal corresponding to the value of τ ^* _min is received at the first inputs of the second division block 16 and the second multiplication block 17 from the sixth output of the memory block 1. In the second division block 16, a signal is generated as a result of integer division N = τ ₁ / τ ^* _min and transmitted to the second multiplication block 17, where the desired value τ ^subtract ₁ = Nτ ^* _min is calculated and transmitted to the output of the device. At the same time, the control signal from the output of the multivibrator 13 through the second delay element 12 is fed directly to the second input of the time sensor 7, setting it to zero. In addition, the output signal of the second delay element 12 through the OR circuit 20 starts the time sensor 7 and transfers the output signal of the shift register 19 by one step, which ensures the reading of the initial data from the memory unit 1 for the second subsystem, and the operation of the device is repeated, but with new ones input values.

After calculating τ ^subt _i corresponding to the last subsystem of the system under study, the operation of the device ends.

The positive effect that the proposed technical solution provides is that the device allows, on the basis of the principle of multiplicity, to determine the periods of maintenance of subsystems of a complex system. The practical implementation of the proposed solution is more rational in terms of spending material and time resources, organizing the maintenance of the system and using the reliable resources of the subsystems.

Information sources

1. Druzhinin G.V. Maintenance processes of automated systems. - M .: Energy, 1973.

2. Barzilovich E.Yu. Maintenance models for complex systems. - M.: Higher School, 1982.

3. Abramenko B.S., Maslov A.Ya., Nemudruk L.N. Operation of automated control systems. USSR Ministry of Defense, 1984.

4. Vorobev G.N., Grishin V.D., Denchenkov V.A. A.S. USSR No. 1320825, M. Cl. 4 G07C 3/08, 1987.

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

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

7. Grishin V.D., Manuylov Yu.S., Schenev A.N. RF patent No. 2206123, M. Cl. 7 G07C 3/08, 2003.

Claims (1)

A device for determining the optimal time program for system maintenance, containing three delay elements, an OR circuit, a time sensor, the output of which is connected to the second input of the third adder, the output of which is connected to the second input of the second adder, a memory unit, the fourth input of which is the fourth input of the device, and the third output, designed to output the set values of the periods of service of the system’s means, is connected to the first input of the nonlinearity block, the output of which is connected to information the integrator’s input and the second input of the first multiplication unit, the output of which is connected to the first input of the first adder, the output of which is connected to the first input of the subtractor, the output of which is connected to the first input of the first division unit, the output of which is connected to the second input of the comparison unit, the second output of which the multivibrator is connected to the control input of the memory element and the enabling input of the key, the information input of which is connected to the output of the memory element, characterized in that a second division block is inserted into it, the second a swarm multiplication unit and a shift register, the first input of which is the first input of the device and connected through the first delay element to the first input of the OR circuit, the second input is connected to the output of the OR circuit and to the second input of the time sensor, and each of n outputs is individually connected to the corresponding control the input ln of the memory block, the second, third, fifth, sixth and seventh inputs of which are the corresponding information inputs of the device, and the first output, designed to output the specified allowable values of the coefficients When the system means, it is connected to the first input of the comparison unit, the first output of which is connected to the third input of the time sensor, the first input of which is connected to the second input of the OR circuit directly, and through the second delay element it is connected to the output of the multivibrator and the control input of the integrator, the output of which is connected to the second input of the subtractor, the first input of which is connected to the second input of the first division block, the second output of the memory block, designed to output the set values of the difference of the average duration of the pre prophylactic prevention and the average duration of emergency recovery work, connected to the first input of the first multiplication block, the fourth output of the memory block, designed to display the set values of the sum of the average duration of the state monitoring and the average duration of emergency recovery work, is connected to the first input of the second adder, the output of which connected to the second input of the first adder, and the second input is connected directly to the second input of the nonlinearity block, and through the third element LCD - with the information input of the memory element, the fifth output of the memory unit, designed to output the specified optimal values of the service periods of the system tools under study, is connected to the first input of the third adder, the sixth output of the memory unit, designed to display the optimal values of the service period of the least reliable system tools, is connected to the first inputs of the second multiplication block and the second division block, the second input of which is connected to the key output, and the output to the second input of the second multiplication block, the output which is the output of the device.

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