Celso Munaro

Celso Munaro
Universidade Federal do Espírito Santo | UFES · Departamento de Engenharia Elétrica

Dr

About

69
Publications
2,861
Reads
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287
Citations
Citations since 2017
21 Research Items
176 Citations
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20172018201920202021202220230102030
20172018201920202021202220230102030
20172018201920202021202220230102030
Additional affiliations
January 1992 - December 2015
Universidade Federal do Espírito Santo
Position
  • Professor

Publications

Publications (69)
Conference Paper
Full-text available
Abstract: Offshore oil and gas production units need to treat and dispose their produced water respecting the limits and reference measurement methods imposed by current laws. The main index to be controlled of this treatment process is the Total Oil and Grease (TOG) in the water to be discarded, which has its official value available for only abou...
Article
The prompt detection and diagnosis of anomalies in oil wells are fundamental to reduce production losses, maintenance costs and to avoid environmental damage. In this paper, a proposal for detecting such anomalies using Long Short-Term Memory (LSTM) autoencoder and one-class Support Vector Machine (SVM) is presented. A public dataset with instances...
Conference Paper
Full-text available
Água produzida, em plataformas marítimas, é um dos efluentes recuperados de poços em conjunto com petróleo e gás natural, sendo o principal resíduo gerado nesse processo. O Teor de Óleos e Graxas (TOG) é considerado um dos principais parâmetros de controle do descarte de água produzida no mar, com limites diários e mensais definidos pela legislação...
Article
This paper presents a multivariate linear contribution analysis in the context of fault detection, isolation and diagnosis. The usually univariate contribution analysis in fault isolation is improved by the use of feature selection. The fault index and the individual contributions of the variables are calculated by Probabilistic Principal Component...
Thesis
Full-text available
Pneumatic valves can be found in the most diverse industrial parks and are used daily in the most diverse control meshes. However, when exposed to the most diverse climatic factors, they tend to increase the friction between their moving parts. When grip occurs, it is common to cause process variability, reducing mesh performance and increasing pro...
Article
This work proposes a classification model for fault diagnosis. In a first stage, an unsupervised clustering algorithm discovers groups of potential fault classes. Subsequently, a specialized classifier is trained for each of the clusters, thus diminishing complexity and augmenting performance. The quality of the diagnosis is further improved by com...
Conference Paper
Full-text available
The correct functioning of the control valves proves to be of great importance in order to obtain the efficiency of the industrial processes. Eliminating the variability in control loop introduced by oscillations from friction has become important. The present work proposes the integration of a friction compensator with variable amplitude in a cont...
Article
A novel model free stiction compensation scheme is developed which eliminates the oscillations and also reduces valve movement, allowing good setpoint tracking and disturbance rejection. Pulses with varying amplitude are added to the controller output to overcome stiction and when the error becomes smaller than a specified limit, the compensation c...
Article
The presence of friction in control valves produces limit cycles that reduces the performance of control loops. Once friction is detected, its compensation avoids process stops until the next maintenance stop is performed. Model free methods adding feed-forward pulses to PID controller output have been proposed to reduce the effect of friction. A c...
Article
Isolation of plant-wide faults in large-scale complex systems is particularly challenging. A methodology to detect and isolate faults is proposed, detecting the faulty variables using univariate control charts and the causality information between them to indicate the source. The clustering of faulty variables uses univariate analysis to avoid the...
Conference Paper
This work presents a framework for fault detection and diagnosis of multimode industrial processes. It is shown that the proposed method to generate features for the faults provides a generalization that can allow the fault diagnosis in modes for which no training was performed. The proposed method is applied to a sophisticated simulator of a conti...
Article
A modular diagnosis system (MDS), based on the framework of fuzzy logic, is proposed for upflow anaerobic sludge blanket (UASB) reactors treating sewage. In module 1, turbidity and rainfall information are used to estimate the influent organic content. In module 2, a dynamic fuzzy model is used to estimate the current biogas production from on-line...
Article
The detection of causal interactions between variables from time series data is an important problem in many research areas. Granger causality is a well-known approach that uses prediction error to infer causality. However, the autoregressive models fitted to data usually do not pass model validation tests based on residual analysis, resulting in l...
Article
In recent years, the development of technologies for automating homes and buildings has highly increased, boomed mainly by wireless communication and microcontrollers development. The problem is that the cost is hardly attractive resulting in applications usually in fancy buildings. However, a great variety of features is currently available on mob...
Conference Paper
Full-text available
Stiction is one of the most adverse non-linearities that can affect a control valve. It impacts both valve longevity and product quality. Currently available stiction compensation methods either reduce the amplitude of oscillation at a cost of increased frequency or require knowledge about process and valve models. In this study a novel stiction co...
Article
In this paper, different approaches for friction estimation and compensation in an inverted pendulum are compared. The Coulomb, static, and viscous frictions are estimated using data only from a closed-loop operation. A control law using linear state feedback is designed to stabilize the pendulum, but limit cycles appear due to friction. Methods ba...
Conference Paper
The discovery of cause-effect relationships in signals from industrial processes is a challenging problem. A data-driven method to achieve this relation is the transfer entropy, a method based on the conditional probability density functions that measures directionality of variation. This method requires several parameters that must be properly cho...
Conference Paper
The problem of detecting causality, from routine operating data, is reviewed from a system identification perspective. It is shown that even simple examples from the literature under Granger causality analysis do not have adequate model fit. As an alternative, this study uses the system identification platform to capture causality from process data...
Article
Stiction in control valves is a frequent cause of loop performance deterioration. The solution is maintenance, but since plant shutdown to perform this task can take a long time, loop performance improvement through stiction compensation affords increased efficiency and profitability by reducing the necessity for unscheduled plant shutdowns. Non-mo...
Article
The oscillations caused by static friction (stiction) in control valves cause losses in quality and expense of raw materials. The effects of friction can be reduced through compensation techniques, until the maintenance of the valve is made in the next programmed plant shutdown. In this work, a well-known stiction compensation method that reduces v...
Conference Paper
The inverted pendulum contains non-negligible nonlinearities due to friction, causing limit cycles. In this paper, a recently proposed method is applied to estimate friction using only data from the closed loop operation. The estimate is compared with the results of open loop tests, showing their similarity. The friction compensation is carried out...
Conference Paper
The problem of disturbance propagation in industrial process control loops has received considerable attention. Causes of plant-wide disturbances include non-linear limit cycles in control loops, controller interactions and tuning problems. Once oscilattions are detected, knowledge about cause and effect in control loops is fundamental for identify...
Conference Paper
The presence of stiction in control valves often causes oscillations in control loops, with negative effects on quality and cost of goods. Step that follows diagnosis is to quantify this stiction, in order to decide about maintenance or to implement compensators that can improve control loop performance until next plant stop. The describing functio...
Conference Paper
This paper addresses the problem of detecting plant wide oscillations in industrial processes and additionally to realize the root cause analysis. When raw signals with the presence of noise, non periodic perturbations, and very low frequencies are analyzed, even robust algorithms may fail to detect oscillating signals. In this paper, a well know a...
Conference Paper
Full-text available
The inverted pendulum contains non-negligible nonlinearities due to friction, causing limit cycles. Much research has been conducted in the literature to estimate and compensate for this friction. In this paper, a recently proposed method is applied to estimate friction using only data from the closed loop operation. Estimations from open-loop and...
Conference Paper
Full-text available
Resumo: Neste artigo, os atritos presentes em um carrinho que atua sobre um pêndulo invertido são estimados através de duas abordagens, usando dados obtidos em malha fechada. O primeiro método utiliza os ciclos limite originados pelo atrito para obter os parâmetros do modelo de Coulomb mais atrito estático, através do ajuste de elipses aos dados me...
Conference Paper
The presence of friction and other non-linearities is a cause of oscillations in control loops, with negative effects on quality and cost of goods. The method of describing function is traditionally used to predict the period and amplitude of cycles limit control loops. This method is used in this article for detection and quantification of nonline...
Article
Stiction is a common cause of loop performance deterioration. The presence of stiction in the spring-diaphragm type valve is the most frequently found valve problem in the process industry. Methods have been proposed fitting an ellipse to the PV-OP plot and the maximum width of the ellipse is reported as "apparent stiction". An improvement on these...
Article
Full-text available
Buscou-se, neste trabalho, avaliar o efeito do teor de argila sobre o processo de decomposição de lodo de esgoto disposto em solo e propor modelos matemáticos inserindo este efeito em seus parâmetros. Solos com texturas contrastantes originados de uma mesma matriz permitiram estabelecer melhores relações entre o teor de argila, biomassa microbiana...
Article
Full-text available
The objective of this study was to evaluate the effect of clay content on sewage sludge decomposition in soil and to propose mathematical models with clay dependent parameters. Soils with contrasting textures from the same sample matrix allowed better relationships to be derived between clay content, microbial biomass, organic carbon and CO2 produc...
Article
Full-text available
This paper presents the structure of a multiuser system for the teaching and practice of analysis and design of control devices. The system uses the software Matlab as a computer tool support. Several users can have access to the physical devices connected to a central computer server and the connection between the users and the server is done usin...
Article
In this paper, a modular diagnosis system (MDS) based on fuzzy logic which is to be used to upflow anaerobic sludge blanket (UASB) reactors treating sewage is presented. The MDS was developed within the frame of fuzzy logic. It is composed of three fuzzy inference system (FIS) modules. In module 1, turbidity and rainfall information classified unde...
Article
In this paper, we present a fault detection and identification (FDI) system based on analytical redundancy applied to an industrial plant model. Luenberger observer is used to produce residues that feed a fuzzy module for fault detection and isolation. Four different faults in sensors and actuators are diagnosed. Fault values are recovered and robu...
Conference Paper
This paper is concerned with the problem of designing stabilizing controllers for nonlinear systems using feedback linearization with estimated states. It is assumed that the systems under consideration are fully linearizable, but the full state is not completely accessible, so that an observer is included in the loop. Sufficient conditions are set...
Conference Paper
This paper focuses on the exact feedback linearization of a nonlinear plant using estimated states. It is well-known that the separation principle is not guaranteed for nonlinear plants, and appropriate hypothesis are commonly assumed to assure local stability properties. It is shown that the separation principle is valid for the design of observer...
Article
Full-text available
This paper focuses on the tracking control problem for an experimental prototype of a magnetic levitation system. The input-state feedback linearization technique for nonlinear systems and estimated states obtained by a reduced-order observer were used to design the proposed strategy. Computer simulations presented show that stability is assured fo...
Conference Paper
This paper is concerned with the state estimator design problem for uncertain linear continuous-time systems with H<sub>∞</sub> norm and variance constraints. The uncertainty is assumed to be time-variant and norm-bounded and enters into both the state and measurement matrices. It is also assumed that the uncertainty can be modeled so that it has a...
Conference Paper
This paper is concerned with the problem of designing tracking controllers for magnetic levitation systems. Using the input-state feedback linearization technique of nonlinear systems, and considering the structure of the linearizing transformation in the case of magnetic levitation systems, a linear reduced-order observer to estimate the states of...
Conference Paper
This paper studies the problem of robust H<sub>∞</sub> filtering of a class of continuous-time linear systems subject to parameter uncertainty. The class of uncertain systems is described by a state-space model with linear nominal parts and norm-bounded nonlinear uncertainties in the state equation. The proposed problem is the design of an asymptot...
Article
An integrated environment for computer control laboratory experiments running on a network is here proposed. The system integrates physical plants and personal computers equipped with data acquisition boards running MATLAB® in an Ethernet based network. The software is developed in C++ for Windows® and provides routines to perform communication amo...
Conference Paper
The problem of robust stabilization of uncertain systems defined by interval plants is here analyzed. Based on classic control compensation techniques, properties deduced from the thirty-two edge theorem and geometry of the value set of closed loop polynomials of an interval plant, a methodology for the synthesis of stabilizing controllers is propo...
Article
This paper is concerned with the simultaneous stabilization problem for a set of MIMO plants. Some previous results are derived for exploring the set of linear controllers associated to each plant. A special notation allows one to deal with controllers assuring performance related to regions of the complex plane. An algorithm for the simultaneous s...
Chapter
This paper considers the problem of robust stabilization in state space. Based on results related to sets of linear robust controllers, a design methodology is proposed applying deterministic control theory to uncertain systems. Two examples are worked out to demostrate the usefullness of the proposed strategies.
Conference Paper
This paper is concerned with tools for analysis and design of linear state-space systems subject to parametric uncertainties. A methodology for exploration of sets of linear controllers is discussed. A special notation allows one to deal with controllers assuring performance related to regions of the complex plane. The methodology is applied to sta...
Article
This paper considers the problem of robust stabilization in state space. Based on results related to sets of linear robust controllers, a design methodology is proposed applying deterministic control theory to uncertain systems. Two examples are worked out to demostrate the usefulness of the proposed strategies.
Conference Paper
A novel technique for obtaining reduced-order dynamic models from high-order models is proposed. The technique uses Schur decomposition, which is an efficient and stable numerical procedure. Based on different assumptions about system modes, two methods for obtaining reduced-order models are developed. In the first method, the reduced model is deri...
Article
This paper focuses on the control problem of feedback linearizable nonlinear systems with parametric uncertainties. The uncertain parameters are estimated via a series-parallel estimator and the state vector is supposed to be measured. The meas-ured state vector and the estimated parameters are used in the linearizing transformation and in the line...
Article
High-rate anaerobic systems, such as the upflow anaerobic sludge blanket (UASB) reactors, are widely used in municipal and industrial wastewater treatment. Even though UASB reactors have several operational advantages, many industries are still reluctant to use them due to the fact that these reactors usually demand constant monitoring of effluent...
Article
This paper addresses the problem of detecting different frequencies of oscillation occurring simulta-neously in multiple control loops. Although the problem of detecting oscillations is well resolved in the literature, when signals in general subjected to noise, disturbances, nonlinearities, etc. are analyzed, the algorithm may fail or detect a lar...
Article
The oscillations caused by friction (stiction) in control valves cause losses in quality and expense of raw materials. The effects of friction can be reduced through their compensation, until the maintenance of the valve is made in the next pro-grammed plant shutdown. In this work a new method to improve the performance is proposed that improves pe...
Article
This paper presents contributions for quantifying valve stiction in control loops based on fitting an ellipse to con-trolled variable (PV) and controller output (OP) plot. It is shown that for plots close to parallelogram patterns (flow loops, e.g) the proposed method produces better estimates compared to existing quantification methods based on th...
Article
RESUMO Este trabalho apresenta um sistema de supervisão via Internet de uma estação de tratamento de esgoto sanitário (ETE) implantado em uma ETE experimental na UFES. Tem por finalidade prover informações de operação em tempo real bem como históricos de dados de operação a qualquer usuário conectado à Internet. Estas informações são utilizadas par...
Article
In this paper a data driven model for modeling dynamics and most commonly found nonlinearities in pneumatic control valves is proposed. All model parameters are obtained through application of signals in the valve to obtain static and dynamic behavior. The simulation results are validated via comparison to those generated by a physical model from l...

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