RU2820568C1 - Method and device for determining operational readiness of object of equipment - Google Patents

Abstract

FIELD: aviation; measurement.

SUBSTANCE: group of inventions relates to methods and devices for monitoring and control, during operation and maintenance of aircraft equipment (AE), for which it is required to determine optimal periods of control and maintenance of articles, which provide the required reliability and readiness of articles for use. Disclosed is a method including determining the state of an object of equipment - an operable state, a state of recovery under operating conditions, when on the basis of performed diagnostics and detection of deviations of separate characteristics and parameters of equipment from required values performing maintenance works, state of early suspension from operation, when due to a malfunction, replacement of individual units and elements of the equipment object is carried out and the state of overhaul as a result of critical wear of the equipment object, determination of intensity of faults eliminated during operation, intensity of faults, which led to early suspension from operation, intensity of overhauls, intensity of recovery of serviceable state in operating conditions, intensity of recovery of serviceable state after early suspension from operation and intensity of recovery of serviceable state as a result of overhaul, wherein the value of the operational readiness characteristic of the equipment is determined by formula , where A is a characteristic taking into account downtime of the equipment object, which is in overhaul, early removal from operation or restoration in operation, B is a characteristic taking into account the ratio of values of overhaul life and duration of overhaul of the equipment object.

EFFECT: high accuracy of determining the value of the integrated reliability characteristic ("operational readiness factor") of the equipment by creating a method and device which take into account the time spent on restoring the operability of the equipment object: under operating conditions (OOC) in conditions of early suspension from operation (ESO); in conditions of scheduled overhaul (OH).

2 cl, 2 dwg

Description

The group of inventions relates to methods and devices for monitoring and control, and can find application in scientific research, development work and practice in the operation of technical objects, in particular, in the operation and maintenance of aviation equipment (AT) products, for which it is necessary to determine those ensuring the required reliability periods of control and maintenance of products, and the values of the characteristics of readiness of products for use.

Reliability indicators are characteristics of a technical object that quantitatively characterize reliability, i.e. the property of an object of technology to maintain over time, within established limits, the values of all parameters characterizing the ability to perform the required functions under given conditions of use, maintenance, storage and transportation.

To quantify the reliability characteristics of technical objects, measured (time, frequency) single reliability indicators are used, which characterize only one reliability property and complex reliability indicators, which characterize several reliability properties.

There is a wide class of products for continuous use.

A feature of the functioning of such products is that they remain at any time in one of the following possible states:

- operational when the product is used or can be used for its intended purpose;

- inoperative.

A comprehensive indicator of the quality of operation of such products is the availability factor - a comprehensive characteristic of the reliability of a technical object, which is the ratio of the time of proper operation to the sum of the times of proper operation and forced downtime of the object, taken over the same calendar period.

To move to a probabilistic interpretation of the value of a complex characteristic of an object’s reliability, i.e. determining the probability of a piece of equipment being in working order at a given point in time (“availability coefficient”) corresponding to time e costs are replaced by the intensity of object transitions between states.

It is known (RU 2720382) a device for determining the values of the characteristics of a product's readiness for use, containing a memory block, a timer, four subtractors, eight division blocks, two absolute value determination blocks, four adders, two comparators, two keys, three memory elements, four multiplication blocks , a block for extracting a square root, a block for extracting an integer part, a subtracting counter, a summing-subtracting block, and the output of the eighth division block is connected to the input of the adding-subtracting block, the input of which is connected to the output of the third memory element, the inputs of which are connected to the output of the sixth division block and with the output of the second comparator, respectively. The device allows you to determine the time of onset of gradual failure, determine the optimal maintenance period and the next period of regulated maintenance of the product and the full availability of the product, taking into account gradual and sudden failures. However, the device does not take into account the specifics of operation and maintenance of AT products.

It is known (RU 2580099) a device for determining the value of the characteristics of the readiness of a product for use, containing a memory block, twelve gates, a multivibrator, five adders, an OR circuit, three triggers, four nonlinearity blocks, two accumulating adders, five multiplication blocks, two comparators, two subtractors , two integrators, five delay elements, a memory element, a division unit and a polarized relay. The device allows you to increase the accuracy of determining the values of output quantities by taking into account the difference in the value of the failure rate of the product according to a change in its operating mode. The device refers to monitoring devices for products of periodic use and does not take into account the specifics of operation and maintenance of AT products.

It is known (RU 2275685) a device that allows you to determine the value of the failure rate, ensuring the readiness factor of the product for use is not lower than the specified one, and a device for determining the reliability characteristics of the product, containing a comparison unit, a divider, an adder, a step voltage generator, switches, and delay elements. As a disadvantage of this device, it should be noted that it does not take into account various methods of restoring the functionality of products.

There is a known (SU 704332) method for determining the time between overhauls of a gas turbine installation, in which, in the process of experiments, critical elements of the installation are found that determine the period between overhauls, the moment of appearance of the threshold values of defects of these elements is recorded, and the rate of development of defects in time is measured up to their critical values to determine the equivalent rate of development defects of the installation as a whole and for it - the time between repairs. In this method, the numerical values of resources and availability factors are determined experimentally and are largely intuitive. In this regard, the accuracy of determining the optimal values of the service period and other output values may also be insufficient.

There is a known (RU 2 336 570) method for determining the optimal maintenance period for a product, in which the law of change over time in the failure rate of the product is specified, and after the formation of time intervals between the expected maintenance of the product, the value of the failure rate of the product is calculated for each of the specified time intervals and used when calculating the values of the probability of failure-free operation, the average time of operable condition and the average time of latent failure of a product at a given time interval, after which the value of the relative unproductively consumed resource of the product is found, its value is compared with the value obtained in the previous specified time interval, the process is repeated until a new one is obtained values of the relative wasted resource of the product or fix the previous value of a given time interval as the optimal period between maintenance.

The disadvantage of this method is that only the technical maintenance of the product is taken into account.

There is a known (RU 475854) system for determining the time of the next preventive maintenance of an object, containing an object failure sensor, a failure number counter, a unit for measuring the time between failures, a central processor of the operator's workstation, an information input unit, a display unit, a unit for selecting the law of distribution of random time between failures, a confidence probability selection block, a failure confidence interval determination block, a decision function calculation block, a decision-making block and a fine cost setter, as well as a method for determining the time of the next preventive maintenance of an object, in which, in the time interval from 0 to the i -th control of the object's preventive maintenance count the number ni of failures and measure the time tj between adjacent failures, perform statistical processing of object failures, on the basis of which a histogram of object failures is constructed and, using the Erlang distribution formula of the kth order, select the value of the integer parameter k corresponding to the law of time distribution between object failures, and they also estimate the failure rate of the object λi at each i -th moment of time for a given confidence probability β and calculate the coefficients r _N , r _B , which determine, respectively, the lower and upper limits of the confidence interval of the failure rate; the determination of the optimal time interval between adjacent preventive maintenance works of the object is determined based on the current state of its reliability using a decision function that takes into account time and cost costs.

This system is aimed at determining the optimal time interval between adjacent preventive maintenance works of an object based on the current state of its reliability by taking into account the time and cost costs of carrying out preventive and repair work. At the same time, cost costs, characterized by a high degree of uncertainty, are a factor that is practically impossible to formalize. In addition, the system only records technical maintenance.

The objective and technical result of the claimed group of inventions is to increase the accuracy of determining the value of the complex characteristics of the reliability of a piece of equipment (“availability coefficient”) by creating a method and device that takes into account the time costs of restoring the operability of a piece of equipment:

- under operating conditions (OUE);

- under conditions of early removal from service (DSA);

- under the conditions of a planned overhaul (CR).

Increasing the accuracy of determining the readiness of an object for operation affects the assessment of the quality of operation of a piece of equipment and changes in the mode of its use.

The claimed technical result is achieved by the fact that a method is proposed that includes determining the states of a piece of equipment - an operable state, a state of restoration under operating conditions, when, based on diagnostics and identification of deviations of individual characteristics and parameters of a piece of equipment from the required values, maintenance work is carried out, states of early removal from operation, when, due to a malfunction, work is carried out to replace individual components and elements of a piece of equipment and the state of major repairs as a result of critical wear of the piece of equipment, determining the intensity of faults eliminated during operation, the intensity of faults that led to early removal from operation, the intensity capital repairs, the intensity of restoration of a working condition under operating conditions, the intensity of restoring a working condition after early removal from operation and the intensity of restoring a working condition as a result of a major overhaul, while the value of the operational readiness characteristics of a piece of equipment is determined by the formula , where A is a characteristic that takes into account the downtime of a piece of equipment that is in a state of overhaul, early removal from service or restoration in operation, B is a characteristic that takes into account the ratio of the values between overhaul life and the duration of a major overhaul of a piece of equipment, as well as a device for determining the operational readiness of the facility equipment containing a divider and an adder, characterized in that three dividers, three adders and a multiplier are additionally introduced into it, the first input of the device is connected to the first input (dividend) of the first divider, the second input of the device is connected to the first input (dividend) of the second divider, the third input of the device is connected to the first inputs of the first and third adders, as well as to the first input (dividend) of the third divider, the fourth input of the device is connected to the second input of the first adder, the output of which is connected to the second input (divider) of the first divider, the output of which is connected to the first input of the second adder, the fifth input of the device is connected to the second input of the third adder, the output of which is connected to the second input (divider) of the second divider, the output of which is connected to the second input of the second adder, the third input of which contains the value of one and the output of which is connected to the first input of the multiplier , the sixth input of the device is connected to the second input (divider) of the third divider, the output of which is connected to the first input of the fourth adder, the second input of which contains the value of one and the output of which is connected to the second input of the multiplier, the output of which is connected to the second input (divider) of the fourth divider , the first input (dividend) of which contains the value of one and the output of which is the output of the device.

Unlike analogue inventions, in the claimed method, when determining the operational readiness coefficient, along with the characteristics of phenomena/events associated with the presence of a piece of equipment in the state of “in operation (operable)” and “under major repairs (inoperable)”, phenomena/events are additionally taken into account, associated with the presence of a technical object in the state “removed from operation” and the corresponding measurable (frequency and time) quantitative characteristics that affect the obtaining of reliable information about the state of the technical object and are in a direct cause-and-effect relationship with the declared technical result - increasing the accuracy of determination the value of a complex characteristic of the reliability of a technical object - the readiness of a technical object for operation.

The essence of the claimed method and device is illustrated by drawings:

Figure 1 – state graph of a technical object,

Where:

1 - P (working state);

2 - OUE (state of troubleshooting under operating conditions);

3 - DSA (state of early removal from service due to a malfunction);

4 - KR (state of repair due to exhaustion of resource before major repairs (between repairs));

Figure 2 – functional diagram of a device for determining the operational readiness coefficient of a technical object,

– intensity of faults (receipts of requests) eliminated under operating conditions;

– intensity of malfunctions (receipts of applications) that led to early removal from service;

– intensity (receipt of applications) of planned capital repairs;

− intensity of restoration (servicing of requests) of the working condition under operating conditions;

– intensity of restoration (service of requests) of the working condition after early removal from service;

− intensity of restoration (service of requests) of the working condition as a result of major repairs.

Applications for the CD have priority, which consists of the following: if an application for the CD arrives at a time when the equipment object is in the DSA or OUE state, then the equipment object is sent to the CD because the service life has been exhausted until the first repair period (between repairs); if the equipment is in a repair condition, any applications are rejected.

Kolmogorov’s system of differential equations for the probabilities of states of a technical object (Figure 1):

(1)

Stationary value is obtained by solving for systems of equations:

(2)

The solution to system (2) is the expression:

(3)

Expression (3) can be represented as ,

Where:

- characteristic (value), taking into account the contribution of major repairs, DSA and OUE to downtime caused by the need to restore the operational state of a piece of equipment;

- characteristic (value), taking into account the ratio of the resource before the first major repair (between repairs) and the duration of this repair.

The input signals of the device (Fig. 2) are the following intensities:

- receipt of applications , , ;

- servicing requests , , .

The input of the first adder receives the intensity values And .

From its output the amount goes to the input of the first divider, the intensity goes to its second input (dividend) .

The division result goes to the first input of the second adder.

The input of the third adder receives intensity values And .

From its output the amount goes to the input of the second divider, the intensity goes to its second input (dividend) .

The division result is fed to the second input of the second adder, the third input of which contains the value 1.

From the output of the second adder, value A is supplied to the input of the multiplier.

Intensity also enters the input of the dividend of the third divisor.

Its second input (divider) receives the intensity .

Since its release private arrives at the input of the fourth adder from 1.

From its output, the value B goes to the second input of the multiplier.

From the output of the multiplier, the product A·B is supplied to the input of the fourth divider, from the output of which the value goes to the output of the device.

The correctness of the method and device was verified using a simulation model with an exponential law of distribution of all random variables of the time of receipt of requests and their servicing with the number of implementations N = 10 ^5.

The relative deviation of the value obtained using the claimed method and device from the solution obtained using the simulation model was 8%, which indicates its adequacy.

Thus, the proposed method and device increase the accuracy of determining the complex characteristics of the reliability of a technical object - the probability of being in working condition during operation (“availability coefficient”).

Claims (2)

1. A method for determining the operational readiness of a piece of equipment, including determining the states of the piece of equipment - operable state, state of restoration under operating conditions, when, based on diagnostics and identification of deviations of individual characteristics and parameters of the piece of equipment from the required values, maintenance work is carried out, states of early removal from operation, when, due to a malfunction, work is carried out to replace individual components and elements of a piece of equipment, and the state of major repairs as a result of critical wear of the piece of equipment, determining the intensity of faults eliminated during operation, the intensity of faults that led to early removal from operation , the intensity of major repairs, the intensity of restoration of a working condition under operating conditions, the intensity of restoring a working condition after early removal from operation and the intensity of restoration of a working condition as a result of a major overhaul, while the value of the operational readiness characteristics of a piece of equipment is determined by the formula , where A is a characteristic that takes into account the downtime of a piece of equipment that is in a state of overhaul, early removal from service or restoration in operation, B is a characteristic that takes into account the ratio of the values between overhauls and the duration of a major overhaul of a piece of equipment. 2. A device for determining the value of the operational readiness characteristic of a technical object for implementing the method according to claim 1, containing a divider and an adder, characterized in that three dividers, three adders and a multiplier are additionally introduced into it, and the first input of the device is connected to the first input of the first divider, the second input of the device is connected to the first input of the second divider, the third input of the device is connected to the first inputs of the first and third adders, as well as to the first input of the third divider, the fourth input of the device is connected to the second input of the first adder, the output of which is connected to the second input of the first divider, output which is connected to the first input of the second adder, the fifth input of the device is connected to the second input of the third adder, the output of which is connected to the second input of the second divider, the output of which is connected to the second input of the second adder, the third input of which contains the value of one and the output of which is connected to the first input multiplier, the sixth input of the device is connected to the second input of the third divider, the output of which is connected to the first input of the fourth adder, the second input of which contains the value of one and the output of which is connected to the second input of the multiplier, the output of which is connected to the second input of the fourth divider, the first input of which there is a value of one and the output of which is the output of the device.