Metro Logical Self-check and Evolution of Metrology

8/7/2019 Metro Logical Self-check and Evolution of Metrology

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SANJIB KUMAR JAYPURIA

PRODUCTION ENGINEERING

IIT DELHI

SUPERVISOR- DR. P.V RAO

Metrological self-check and evolution

of metrology


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OBJECTIVES

y The paper deals with the problem regarding measurement

reliability .

y Efficiency of metrological self-check methods in comparison

with conventional methods of metrological maintenance isshown

y Evolution of artificial intelligent sensor in metrological self-

check systems for increasing metrological assurance.


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INTRODUCTION

y Measurement reliability is particularly important parameterin the fields as nuclear power engineering, cosmonautics,aviation.

y The number of measuring instruments embedded in the

equipment increases from year to year and same way theaccident rate.

y However, the method applied to check their serviceability inthe process of operation as many years ago is periodical

calibration, done at intervals of 1 2 years. By which itserror under operating conditions lies within the specifiedlimits.


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y But the conventional methods of the metrological

serviceability control are inefficient.

y It is necessary to control their metrological serviceability

automatically directly in the process of operation which leadsthe concept of metrological self-check.

y Self-check makes it possible both to identify a metrological

defect and to inform an operator about it practically

immediately or even a short time before the critical moment,which allows for excluding the usage of inadequate

information.


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y To fulfill the requirement of self check in a measuring instrumentssensor devices come to picture.

y But they have to operate under a high-strength effect ofinfluencing factors and in many cases, the measurement conditions

changing without any control and this is the reason sensor cantfulfill metrological serviceability.

y In the paper, a solution of this problem is considered andconsequently the purpose of artificial intelligence in a measuringinstrument can be defined.

y which ensure the reliability of measurement instrument for anextended lifetime without any metrological maintenance orperiodical calibration.


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EVOLUTIONOF METROLOGY

y It is found there is an analogy between evolution of the living

organisms system and that of development of the technical

systems, described by Prof. N. Wiener.

y

Applying this idea onto the analogy between evolution ofliving creature sensors and evolution of sensor devices, it is

possible to forecast the development of the sensor devices.

y This analogy shows that survival in living nature and

reliability of information coming from sense organ andsensor devices of living organism and technical system

respectively.


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CALIBRATIONOFINSTRUMENT

y Measurement of accuracy and comparison with standard.

y The purpose of calibration is to ensure that the measuring

accuracy is known over the whole measurement range under

specified environmental conditions for calibration.


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Calibration with sensor

y sensor is the simplest sensitive element or the element of a

measuring instrument or measuring system, which is

directly affected by a phenomenon, body, or substance

carrying a quantity to be measured .

y Control system receives information about the parameters of

technological process from multiple sensors.

y Based on measured values, the control system generates

commands to switch an operation mode and/or to form analarm signal.


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y The key problems of measurement reliability are related to

sensors: their components are ageing and parameters are

changing with time.

y

These sensor errors are due to oxidation of metal;

sublimation of particles from a surface;

mechanical damage of the surface;

diffusion of impurities

All these reasons deteriorate metrological parameters of

sensors and can lead to control errors.


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y The effect of the influencing factor can be weakened by aspecial design of the sensor or by polishing the surface of thesensor and metal where it is operating.

y It is not always possible to develop the sensor with

metrological characteristics which do not depend oninfluencing factors during long period of operation.

y In many cases, it is necessary to interfere in a technologicalprocess in order to carry out a calibration. Such interferences

lead to additional costs.y Any customer does not want to pay for special testing in

order to determine optimal CI for each specific sensor.


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y At present measurement reliability assured by periodiccalibrations of equipments. The level of confidence inmeasurement data depends on the duration of calibration intervals(CI).

y The initial decision in determining the CI is a very complexprocess based on the following factors:

the instrument manufacturers recommendation,

expected extent and severity of use,

the influence of the environment,

the required uncertainty in measurement, adjustment of the individual instrument,

data about the same or similar devices


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y Therefore, most customers are not satisfied with the present

practice of providing the level of confidence in automatic

control system measurements for expensiveness of the

procedure, but it is contradicted by the author that It is

desirable to calibrate measuring instruments as seldom as

possible.

y However, unreliable information coming to the automatic

control system can lead to failures and large economic costs

and it becomes a challenge to solve this contradiction within

the frames of generally accepted methods of measurement

assurance.


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y A purpose of intelligence is to provide the survival of equipment

in the case of unpredictably changing conditions of equipment and

should be assure reliability of measurements during the extended

lifetime without metrological maintenance.

y The system providing an estimation of the reliability of measuringinformation formed in the system through the

automatic check of metrological health of the sensors included in

the system can be called intelligent.

y Intelligence in Nature evolved in two ways: formation ofcollective mind of many living organisms and development of the

intelligence (mind) of a separate individual.


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y Formation of the collective mind is the integration of a numberof autonomous subsystems of a lower level

y When many no of sensor connected in a system, sensors, in whicha metrological fault occurred, can be detected on the basis of

deviation of their signals from the signals of the larger group of theothers included in the system.

y The system providing an estimation of the reliability of measuringinformation formed in the system through the automatic check ofmetrological health of the sensors included in the system can be

called intelligent.y However, it is not always possible to form significantly large

swarm of sensors to measure the same value.


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y swarming model is not the most effective for creation of

the measuring information reliability check due to delay

signal received from machine and which leads to error

decision which show path to a new type of intelligence come

to picture and called as individual intelligence.

y Integration of a number of autonomous sensor. Each of the

sensor was linked with one or several sensing elements and

had individual features and has an advantage with the respect

of the search of the effective ways of survival under changing

environment.


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y The sensor that we call intelligent has the following features:

it includes one or more basic sensing elements as well asadditional elements (additional sensing elements can be such

elements) the combination of all the elements enables to form a

measurement signal as well as additional signals;

these signals contain information about the metrological healthof a sensor (the metrological self-check can be performed);

processing of measurement and additional signals is carried outby microprocessor, that can be installed inside or outside of thesensor.


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y Author described that the economic efficiency of intelligentsensors is significantly higher than the economic efficiency ofintelligent sensor systems.

y This automatic self-check sensors will be able not only to

correct the consequences of ageing and outside impacts, butto change their parameters automatically on the basis of thepredicted changes.

y Metrological self-check of a sensor is the automatic control

of its metrological serviceability in the operating process,which is realized with the help of a reference value( accepted reference value).


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y In the process of operation the intelligent sensors with

metrological self-check can provide:

Practically continuous control of the reliability of

measurement information.Automatic correction of the sensor parameters.

Measurements under operation conditions with minimum

cost.

Long term calibration interval can be specified.


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a)Pictorial view of intelligent sensor

b)varition of level of attention towards metrological self check.


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CONCLUSION

y Present-day technologies created a basis for the development ofthe intelligent sensors.

y The functions of intelligent sensors are self correction, faulttolerance, and forecasting the sensor metrological health. The

innovations in the area of the metrological self-check shows a pathfor an advanced age of metrology.

y Somehow it is also increasing the set up cost and it leads to higherprice upon end user. It is reducing human effort and making themmachine depended.

y Sensor manufacturing technologies are improving. However, onlyrare researchers keep the interest in search of new approaches tothe assuring the traceability of measurements.


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y To my point of view, the development ofintelligent sensors

with metrological self-check is the necessary stage of

automation of measuring instruments metrological

maintenance.

y The task of a future work is, to develop new intelligent

sensors with metrological self-check function and secondly

to promote mass-production of such intelligent sensors.


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REFERENCES

1- Metrological self-check and evolution of metrology by RoaldTaymanov, Ksenia Sapozhnikova

2-A self-validating digital Coriolis mass-flow meter: anoverview by M. P. Henry

3- Topical tasks of metrology due to measuring instrumentscomputerization Valery S. Aleandrov, Roald E. Taymanov,Anna G. Chunovkina

4-Problems of terminology in the field of intelligent sensors

and systems Roald Taymanov, Ksenia Sapozhnikova5-www.sciencedirect.com

6-www.wikipedia.com


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Date post:	08-Apr-2018
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Metro Logical Self-check and Evolution of Metrology

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