The Trade-Off between the Controller Effort and Control Quality on Example of an Electro-Pneumatic Final Control Element

Mapping Intimacies ◽

10.20944/preprints201901.0002.v1 ◽

2019 ◽

Author(s):

Michał Bartyś ◽

Bartłomiej Hryniewicki

Keyword(s):

Control Element ◽

Time To Failure ◽

Quality Factors ◽

Level Control ◽

Control Value ◽

Control Quality ◽

Embedded Controller ◽

Pneumatic Transducer ◽

And Control ◽

Mean Time

For many years, the programmable positioners have been widely applied in structures of modern electro-pneumatic final control elements. The positioner consists of an electro-pneumatic transducer, embedded controller and measuring instrumentation. Electro-pneumatic transducers that are used in positioners are characterized by a relatively short mean time-to-failure. The practical and economical method of a reasonable prolongation of this time is proposed in this paper. It is principally based on assessment and minimizing the effort of the embedded controller. For this purpose, were introduced: the control value variability, mean-time and the cumulative controller's effort. The diminishing of controller effort has significant practical repercussions, because it reduces the intensity of mechanical wear of the final control element components. On the other hand, the reduction of the cumulative effort is important in the context of process economy due to limitation of the consumption of energy of compressed air supplying the final control element. Therefore, the minimization of introduced effort factors has an impact on increasing the functional safety and economics of the controlled process. As a result of the performed simulations, the recommendations regarding the selection of the structure and tuning of positioner controller were elaborated. The simulations were performed in the Matlab-Simulink environment with the use of the liquid level control system in which a phenomenological model of a final control element was deployed. It has been proven that under appropriate conditions, it is possible to extend significantly the lifetime of the final control element and simultaneously enhance the control quality factors.

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The Trade-Off between the Controller Effort and Control Quality on Example of an Electro-Pneumatic Final Control Element

Actuators ◽

10.3390/act8010023 ◽

2019 ◽

Vol 8 (1) ◽

pp. 23 ◽

Cited By ~ 2

Author(s):

Michał Bartyś ◽

Bartłomiej Hryniewicki

Keyword(s):

Control Element ◽

Time To Failure ◽

Level Control ◽

Control Effort ◽

Control Value ◽

Embedded Controller ◽

Pneumatic Transducer ◽

And Control ◽

Mean Time ◽

Selection Of

For many years, the programmable positioners have been widely applied in structures of modern electro-pneumatic final control elements. The positioner consists of an electro-pneumatic transducer, embedded controller, and measuring instrumentation. Electro-pneumatic transducers that are used in positioners are characterized by a relatively short mean time-to-failure. The practical and economical method of a reasonable prolongation of this time is proposed in this paper. It is principally based on assessment and minimizing the effort of the embedded controller. For this purpose, some measures were introduced: The control value variability, mean-time, and the cumulative controller’s effort. The diminishing of controller effort has significant practical repercussions because it reduces the intensity of mechanical wear of the final control element components. On the other hand, the reduction of the cumulative effort is important in the context of process economy due to limitation of the consumption of energy of compressed air supplying the final control element. Therefore, the minimization of control effort indicators has an impact on the increase of the functional safety and economics of the controlled process. The simulations were performed in the Matlab-Simulink environment with the use of the liquid level control system in which a phenomenological model of a final control element was deployed. As a result of the performed simulations, the recommendations regarding the selection of the structure of positioner controller were elaborated.

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POSSIBILITY TO REDUCE THROMBOCYTOPENIA AFTER CHEMORADIOTHERAPY IN ONCOLOGICAL PATIENTS

Problems in oncology ◽

10.37469/0507-3758-2017-63-3-466-469 ◽

2017 ◽

Vol 63 (3) ◽

pp. 466-469

Author(s):

Luiza Korytova ◽

Aleksey Meshechkin ◽

Oleg Korytov ◽

V. Krasnikova

Keyword(s):

Combined Treatment ◽

Treated Group ◽

Median Number ◽

Blood Analysis ◽

Control Group ◽

Level Control ◽

Normal Range ◽

Oncological Patients ◽

Level Increase ◽

And Control

Objective was to establish efficiency of sodium nucleospermat in correcting thrombocytopenia after chemoradiotherapy in oncological patients. Methods and materials. The study included data on 32 patients that had undergone combined treatment from January till May 2016. After detecting thrombocytopenia patients were randomized into two groups (16 patients in each): treated group, where patients received sodium nucleospermat, and control group, where sodium nucleospermat was not used. Thrombocyte level control was done on 5th, 10th and 15th day after treatment was over. Results and discussion. All 16 patients showed positive dynamics in increasing thrombocyte level after Sodium nucleospermat injection course was finished. This was proven by first (5th day) blood analysis. On average thrombocyte level after sodium nucleospermat treatment has risen to normal, at 161х109/1. Only 3 patients from this group had to pause radiotherapy for 5 days. Control group patients, which did not receive sodium nucleospermat, showed evidence of thrombocyte level recovery by 10th day only. On average thrombocyte level increase was insignificant, and median number was 111*109/l. Low thrombocyte level was main reason to pause radiotherapy for 11 (69%) patients in control group. Conclusion. Sodium nucleospermat allowed raising thrombocyte level to the lower normal range, which surpassed by 40%-50% in control group patients. Use of sodium nucleospermat did not show any cases of allergic reactions, toxicity or complications in oncological patients.

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Surveillance System in Smart Cities: A Dependability Evaluation Based on Stochastic Models

Electronics ◽

10.3390/electronics10080876 ◽

2021 ◽

Vol 10 (8) ◽

pp. 876

Author(s):

Igor Gonçalves ◽

Laécio Rodrigues ◽

Francisco Airton Silva ◽

Tuan Anh Nguyen ◽

Dugki Min ◽

...

Keyword(s):

Surveillance System ◽

Smart Cities ◽

Heterogeneous Data ◽

Time To Failure ◽

Video Streams ◽

Dependability Evaluation ◽

The Mean ◽

Mean Time ◽

The Internet Of Things

Surveillance monitoring systems are highly necessary, aiming to prevent many social problems in smart cities. The internet of things (IoT) nowadays offers a variety of technologies to capture and process massive and heterogeneous data. Due to the fact that (i) advanced analyses of video streams are performed on powerful recording devices; while (ii) surveillance monitoring services require high availability levels in the way that the service must remain connected, for example, to a connection network that offers higher speed than conventional connections; and that (iii) the trust-worthy dependability of a surveillance system depends on various factors, it is not easy to identify which components/devices in a system architecture have the most impact on the dependability for a specific surveillance system in smart cities. In this paper, we developed stochastic Petri net models for a surveillance monitoring system with regard to varying several parameters to obtain the highest dependability. Two main metrics of interest in the dependability of a surveillance system including reliability and availability were analyzed in a comprehensive manner. The analysis results show that the variation in the number of long-term evolution (LTE)-based stations contributes to a number of nines (#9s) increase in availability. The obtained results show that the variation of the mean time to failure (MTTF) of surveillance cameras exposes a high impact on the reliability of the system. The findings of this work have the potential of assisting system architects in planning more optimized systems in this field based on the proposed models.

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On classes of life distributions based on the mean time to failure function

Journal of Applied Probability ◽

10.1017/jpr.2020.91 ◽

2021 ◽

Vol 58 (2) ◽

pp. 289-313

Author(s):

Ruhul Ali Khan ◽

Dhrubasish Bhattacharyya ◽

Murari Mitra

Keyword(s):

Damage Model ◽

Replacement Policy ◽

Time To Failure ◽

Mean Time To Failure ◽

Moment Convergence ◽

Life Distributions ◽

Cumulative Damage Model ◽

The Mean ◽

Age Replacement ◽

Mean Time

AbstractThe performance and effectiveness of an age replacement policy can be assessed by its mean time to failure (MTTF) function. We develop shock model theory in different scenarios for classes of life distributions based on the MTTF function where the probabilities $\bar{P}_k$ of surviving the first k shocks are assumed to have discrete DMTTF, IMTTF and IDMTTF properties. The cumulative damage model of A-Hameed and Proschan [1] is studied in this context and analogous results are established. Weak convergence and moment convergence issues within the IDMTTF class of life distributions are explored. The preservation of the IDMTTF property under some basic reliability operations is also investigated. Finally we show that the intersection of IDMRL and IDMTTF classes contains the BFR family and establish results outlining the positions of various non-monotonic ageing classes in the hierarchy.

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ACTION MODE, PERSISTENCE AND CONTROL VALUE OF FIPRONIL FOR RICE GRASSHOPPERS OXYA (ORTHOPTERA: CANTANTOPIDAE)

Insect Science ◽

10.1111/j.1744-7917.1999.tb00011.x ◽

1999 ◽

Vol 6 (1) ◽

pp. 62-70 ◽

Cited By ~ 2

Author(s):

Zhibin Liu ◽

Mingqing Wu ◽

Zhiyong Deng ◽

Qingchuan Wang ◽

Hanwu Chen ◽

...

Keyword(s):

Control Value ◽

Action Mode ◽

And Control

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Contribution to Rolling Bearing Reliability Modeling

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.110-116.2497 ◽

2011 ◽

Vol 110-116 ◽

pp. 2497-2503 ◽

Cited By ~ 1

Author(s):

Zdenek Vintr ◽

Michal Vintr

Keyword(s):

Operating Time ◽

Rolling Bearing ◽

Time To Failure ◽

Rolling Bearings ◽

Mean Time To Failure ◽

Reliability Modeling ◽

Time Between Failures ◽

Large Groups ◽

Mean Time

Rolling bearings are usually considered to be non-repaired items the reliability of which is characterized by mean time to failure, or so called basic rating life. Reliability describes these parameters well in case the bearings are used in operation up to the very time the failure occurs, or during the time corresponding with basic rating life. In case of railway applications the bearings are often used in large groups and are preventively replaced after much shorter operating time as compared with their basic rating life. In the article there is a model which enables us to describe the bearings reliability in this specific case and to specify a number of failures which might be expected from a group of bearings during operating time, or to determine mean operating time between failures of bearings.

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Filling machine preventive maintenance using age replacement method in PT Lucas Djaja

MATEC Web of Conferences ◽

10.1051/matecconf/201815401056 ◽

2018 ◽

Vol 154 ◽

pp. 01056

Author(s):

Fifi Herni Mustofa ◽

Ria Ferdian Utomo ◽

Kusmaningrum Soemadi

Keyword(s):

Maintenance Cost ◽

Time To Failure ◽

High Failure Rate ◽

Corrective Maintenance ◽

Replacement Method ◽

Critical Components ◽

Age Replacement ◽

Engine Maintenance ◽

A Company ◽

Mean Time

PT Lucas Djaja is a company engaged in the pharmaceutical industry which produce sterile drugs and non-sterile. Filling machine has a high failure rate and expensive corrective maintenance cost. PT Lucas Djaja has a policy to perform engine maintenance by way of corrective maintenance. The study focused on the critical components, namely bearing R2, bearing 625 and bearing 626. When the replacement of the failure done by the company is currently using the formula mean time to failure with the result of bearing R2 at point 165 days, bearing 625 at a point 205 days, and bearing 626 at a point 182 days. Solutions generated by using age replacement method with minimization of total maintenance cost given on the bearing R2 at a point 60 days, bearing 625 at the point of 80 days and bearing 626 at a point 40 days.

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A Bayesian Estimation of Reliability Measures of Stepwise Exponential Distribution System

9th Biennial Conference on Reliability, Stress Analysis, and Failure Prevention ◽

10.1115/detc1991-0005 ◽

1991 ◽

Author(s):

M. H. Hu

Keyword(s):

Bayesian Estimation ◽

Exponential Distribution ◽

Distribution System ◽

Failure Process ◽

Reliability Function ◽

Distribution Model ◽

Time To Failure ◽

Reliability Measures ◽

In Series ◽

Mean Time

Abstract This paper presents an analysis method for reliability measures of a system with step changes in failure and repair rates. Both failure and repair time have exponential function of time. Such a system is called a stepwise exponential distribution system. This kind of failure process can take place in various equipments. This paper deals with the system having components in series arrangement. Bayesian statistics is used in defining prior and posterior probability density functions of failure and repair rates. These functions provide information for the estimation of reliability measures: 1) failure and repair rates, 2) mean time to failure, 3) mean time to repair, 4) reliability function and 5) availability. A sample problem is given to illustrate the methodology. The Bayesian estimation of the stepwise exponential distribution model is useful in the planning of equipment predictive maintenance.

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