Luis Cláudio Oliveira-Lopes | Universidade Federal de Uberlândia (original) (raw)
Papers by Luis Cláudio Oliveira-Lopes
Sensors, 2022
Path planning techniques are of major importance for the motion of autonomous systems. In additio... more Path planning techniques are of major importance for the motion of autonomous systems. In addition, the chosen path, safety, and computational burden are essential for ensuring the successful application of such strategies in the presence of obstacles. In this context, this work introduces a modified potential field method that is capable of providing obstacle avoidance, as well as eliminating local minima problems and oscillations in the influence threshold of repulsive fields. A three-dimensional (3D) vortex field is introduced for this purpose so that each robot can choose the best direction of the vortex field rotation automatically and independently according to its position with respect to each object in the workspace. A scenario that addresses swarm flight with sequential cooperation and the pursuit of moving targets in dynamic environments is proposed. Experimental results are presented and thoroughly discussed using a Crazyflie 2.0 aircraft associated with the loco position...
This work presents a rescheduling strategy based on a model predictive closed-loop algorithm with... more This work presents a rescheduling strategy based on a model predictive closed-loop algorithm with shrinking horizon based on uncertain models. This formulation can address most of the rescheduling needs of a chemical production operation. The strategyis based on a quantitative model to forecast the effects of process operation changes and disturbances in the production goal by using uncertain models. The studied problem is based on a model predictive control algorithm that uses a set of state-space models to describe all possible scenarios with uncertain properties. It also evaluates the properties and features of the closed-loop rescheduling algorithm based on closed-loop performance objectives. A comparison with standard scheduling strategies is performed showing the great potential of the closed-loop dynamic rescheduling algorithm.
A distributed model predictive control (DMPC) strategy brings interesting features of topology, f... more A distributed model predictive control (DMPC) strategy brings interesting features of topology, flexibility and maintenance to large-scale nonlinear systems. This work introduces two new cooperative distributed nonlinear model predictive control strategies with automatic partitioning. The first approach is based on oriented graphs of the linearized model of the plant and the second one based on incidence matrices of the nonlinear model of the plant. The proposed strategies were applied to a benchmark plant and compared to other control structures, obtaining promising results.
International Journal of Systems Science, 2021
Model structure selection for nonlinear system identification has been widely studied over the la... more Model structure selection for nonlinear system identification has been widely studied over the last 30 years due to its great importance. There are many methods in the literature to deal with structure selection, although these methods have their specific benefits, they face some difficulties in selecting the structure for a parsimonious model. In this paper, two methods based on the Randomised Model Structure Selection (RaMSS) approach are introduced in order to deal with the structure selection problem. The first one is the Randomised Model Structure Selection with Error Reduction Ratio (RaMSS-ERR) that uses the error reduction ratio as a filter for the terms analysis, improving the convergence, and the second one is the Randomised Model Structure Selection with Genetic Inheritance (RaMSS-EGI) that uses a genetic inheritance in order to get a faster convergence. The methods were applied to benchmark models and the results are encouraging. Applications to systems with a large candidate regressor set and to a continuous stirred-tank reactor are also carried out. The results show that the proposed method may be used to identify both linear and nonlinear model structures with a reduced number of iterations, computational time, and number of explored models.
Blucher Chemical Engineering Proceedings, 2017
Proceedings of the 6th International Conference on Nonlinear Science and Complexity, 2016
Computer Aided Chemical Engineering, 2016
Abstract Distributed Model Predictive Control (DMPC) algorithms in which each local controller op... more Abstract Distributed Model Predictive Control (DMPC) algorithms in which each local controller optimizes a global cost function are known as cooperative. This work investigates a cooperative DMPC coupled to an automatic partitioning of the nonlinear system. The local decomposition used is based on the directed graph of the effects on control variables from the space of inputs through a successive linearization of the plant model at each sampling instant. The proposed strategy was applied to a benchmark plant and compared to centralized controller.
Anais do XX Congresso Brasileiro de Engenharia Química, 2015
Anais do XX Congresso Brasileiro de Engenharia Química, 2015
Anais do XX Congresso Brasileiro de Engenharia Química, 2015
RESUMO-As máquinas de vetores de suporte são uma poderosa ferramenta de reconhecimento de padrões... more RESUMO-As máquinas de vetores de suporte são uma poderosa ferramenta de reconhecimento de padrões. Elas representam um conjunto de metodologias do aprendizado supervisionado estatístico que é usado para classificação e análise de regressão de dados. Os vetores de suporte utilizam um hiperplano com máxima margem para separar as diferentes classes de dados. Este trabalho apresenta um sistema de detecção que utiliza as máquinas de vetores de suporte para detectar falhas em processos e realizar o diagnóstico das mesmas. A metodologia baseia-se em informações históricas quantitativas e qualitativas com máquinas de vetores de suporte treinadas e sintonizadas pelo método da evolução diferencial. O sistema de detecção de falhas foi avaliado em processos químicos para verificar a adequabilidade da proposta para a detecção e classificação de falhas com dados históricos e qualitativos. Métricas de desempenho do sistema apontam para a eficiência do sistema de detecção nos cenários investigados.
Anais do XX Congresso Brasileiro de Engenharia Química, 2015
Computer Aided Chemical Engineering, 2012
Abstract This paper presents the application of reconfigurable control strategy to a multivariabl... more Abstract This paper presents the application of reconfigurable control strategy to a multivariable neutralization process under several fault scenarios. The combined control strategy is integrated to a reconfiguration block that uses the available signals from the remaining sensors and actuators to reconstruct a signal useful to the nominal controller leading to a stable closed-loop behavior even in the presence of faults. Simulations results show that, although the overall system performance can be compromised, the reconfigurable control strategy leads to a system that is still able to operate within acceptable performance in the studied fault scenarios.
Materials Science Forum, 2012
Mathematical models for thickeners can be used for equipment design, to simulate the process oper... more Mathematical models for thickeners can be used for equipment design, to simulate the process operation, and to develop control strategies for a continuous operation. In this work, numerical simulation to obtain the final height of the sediment when operating at steady state conditions were performed using two mathematical models: the model introduced by Tiller and Chen (1988) and the one proposed by Arouca (2007). The simulated results were compared to experimental data obtained when the thickener was operated with and without the use of flocculent agent. The equipment used to obtain experimental data was a conventional thickener, built in acrylic. Aluminum sulfate was used in the experiments for the production of flocculated suspensions. The results showed that the Tiller and Chen (1988) model produced a deviation of 39.0% for kaolin suspensions and 14.3% when aluminum sulfate was added to the system. The Arouca (2007) model resulted in values much closer to those obtained experime...
labplan.ufsc.br
Page 1. CONTROLE TOLERANTE A FALHAS DE UMA COLUNA DE DESTILA¸C˜ AO Lucas Lacerda Gomes Reis ∗, Lu... more Page 1. CONTROLE TOLERANTE A FALHAS DE UMA COLUNA DE DESTILA¸C˜ AO Lucas Lacerda Gomes Reis ∗, Luıs Cláudio Oliveira-Lopes∗ ...
The interdisciplinary journal of Discontinuity, Nonlinearity, and Complexity, 2018
In this work, the variation of time and amplitude of the electrical stimulation of the heart musc... more In this work, the variation of time and amplitude of the electrical stimulation of the heart muscle is analyzed during respiratory control exercise, effect of the autonomic nervous system. The specifics are verified by recurrence plot, and recurrence quantification analysis. The analysis revealed distinguished behavior of the electrical stimulation of the heart. And, the cross recurrence between the variations of amplitude and time demonstrated the equilibrium relationship in the cardiac cycles, which are accentuated in the exercise of concentration.
posgrad.mecanica.ufu.br
... Fran Sérgio Lobato franpi22@yahoo.com.br Faculdade de Engenharia Mecânica Valder Steffen Jr v... more ... Fran Sérgio Lobato franpi22@yahoo.com.br Faculdade de Engenharia Mecânica Valder Steffen Jr vsteffen@mecanica.ufu.br Faculdade de Engenharia Mecânica ... Lobato, FS and Steffen, V., 2007, “Engineering System Design with Multi-Objective Differential Evolution”. ...
2021 14th IEEE International Conference on Industry Applications (INDUSCON), 2021
Fault detection and diagnosis in modern control systems have been of constant interest in recent ... more Fault detection and diagnosis in modern control systems have been of constant interest in recent publications. Its progress is a consequence of the requirements imposed by the development of other technologies through demands on security operations, guarantee of the required functions execution, reduction of costs, and optimization of maintenance tasks. In order to provide the survey in this area, the article discriminates the main fault detection and diagnosis techniques, allowing the reader to acquire, in different practice scenarios, an ability to discern the possibilities of applying the methods in focus. The text is divided in signal analysis-based methods, model-based methods, data-driven methods, and hybrids methods. The conclusion exposes the main global limitations in the area as possible subjects for future works.
2021 14th IEEE International Conference on Industry Applications (INDUSCON), 2021
This paper highlights the design of an adaptive observer based on radial basis function neural ne... more This paper highlights the design of an adaptive observer based on radial basis function neural network (RBFNN) for the diagnosis of actuator faults in a quadrotor UAV (Unmanned Aerial Vehicle), and the design of a fault-tolerant control system. First, the quadrotor UAV model considering the faults and unknown disturbances is presented. Next, the adaptive observer design is implemented using a reduced order model of the system, in order to simplify the structure of the neural network and consequently reduce the computational complexity and facilitate the adjustment of its parameters. The fault-tolerant control system is then exposed through the combination of the controller and the faults estimated by the adaptive observer. Simulations are performed in order to demonstrate the effectiveness of the proposed system with respect to the speed and accuracy of faults estimation with nonlinear behaviors and simultaneous occurrences in the actuators, and the attenuation of the effects of faults on the quadrotor UAV dynamics.
IEEE Latin America Transactions, 2019
Quadrotor helicopters are gaining notoriety as research platform of unmanned aerial vehicle (UAV)... more Quadrotor helicopters are gaining notoriety as research platform of unmanned aerial vehicle (UAV), due to its mechanical simplicity and high maneuverability, as well as the ability to hover and perform vertical takeoff and landing (VTOL). However, the development of control systems for such vehicles is not trivial. Quadrotors have a nonlinear and open-loop unstable behavior and they are constantly affected by aerodynamic disturbances and unmodeled dynamics. In this article, a cascade PID control strategy designed for stabilization and path tracking of an unmanned quadrotor is presented. The dynamic motion equations are obtained by the Lagrange-Euler formalism. The proposed control structure consists of an outer loop for the translational movements, followed by an inner loop for the stabilization of the quadrotor's attitude motions. Simulations and experimental results check the performance achieved with the proposed control strategy. The aircraft used is the Crazyflie 2.0 and the state estimation is accomplished through an extended Kalman filter, where information from the inertial measurement unit is fused with positional information from an ultra-wideband system.
Sensors, 2022
Path planning techniques are of major importance for the motion of autonomous systems. In additio... more Path planning techniques are of major importance for the motion of autonomous systems. In addition, the chosen path, safety, and computational burden are essential for ensuring the successful application of such strategies in the presence of obstacles. In this context, this work introduces a modified potential field method that is capable of providing obstacle avoidance, as well as eliminating local minima problems and oscillations in the influence threshold of repulsive fields. A three-dimensional (3D) vortex field is introduced for this purpose so that each robot can choose the best direction of the vortex field rotation automatically and independently according to its position with respect to each object in the workspace. A scenario that addresses swarm flight with sequential cooperation and the pursuit of moving targets in dynamic environments is proposed. Experimental results are presented and thoroughly discussed using a Crazyflie 2.0 aircraft associated with the loco position...
This work presents a rescheduling strategy based on a model predictive closed-loop algorithm with... more This work presents a rescheduling strategy based on a model predictive closed-loop algorithm with shrinking horizon based on uncertain models. This formulation can address most of the rescheduling needs of a chemical production operation. The strategyis based on a quantitative model to forecast the effects of process operation changes and disturbances in the production goal by using uncertain models. The studied problem is based on a model predictive control algorithm that uses a set of state-space models to describe all possible scenarios with uncertain properties. It also evaluates the properties and features of the closed-loop rescheduling algorithm based on closed-loop performance objectives. A comparison with standard scheduling strategies is performed showing the great potential of the closed-loop dynamic rescheduling algorithm.
A distributed model predictive control (DMPC) strategy brings interesting features of topology, f... more A distributed model predictive control (DMPC) strategy brings interesting features of topology, flexibility and maintenance to large-scale nonlinear systems. This work introduces two new cooperative distributed nonlinear model predictive control strategies with automatic partitioning. The first approach is based on oriented graphs of the linearized model of the plant and the second one based on incidence matrices of the nonlinear model of the plant. The proposed strategies were applied to a benchmark plant and compared to other control structures, obtaining promising results.
International Journal of Systems Science, 2021
Model structure selection for nonlinear system identification has been widely studied over the la... more Model structure selection for nonlinear system identification has been widely studied over the last 30 years due to its great importance. There are many methods in the literature to deal with structure selection, although these methods have their specific benefits, they face some difficulties in selecting the structure for a parsimonious model. In this paper, two methods based on the Randomised Model Structure Selection (RaMSS) approach are introduced in order to deal with the structure selection problem. The first one is the Randomised Model Structure Selection with Error Reduction Ratio (RaMSS-ERR) that uses the error reduction ratio as a filter for the terms analysis, improving the convergence, and the second one is the Randomised Model Structure Selection with Genetic Inheritance (RaMSS-EGI) that uses a genetic inheritance in order to get a faster convergence. The methods were applied to benchmark models and the results are encouraging. Applications to systems with a large candidate regressor set and to a continuous stirred-tank reactor are also carried out. The results show that the proposed method may be used to identify both linear and nonlinear model structures with a reduced number of iterations, computational time, and number of explored models.
Blucher Chemical Engineering Proceedings, 2017
Proceedings of the 6th International Conference on Nonlinear Science and Complexity, 2016
Computer Aided Chemical Engineering, 2016
Abstract Distributed Model Predictive Control (DMPC) algorithms in which each local controller op... more Abstract Distributed Model Predictive Control (DMPC) algorithms in which each local controller optimizes a global cost function are known as cooperative. This work investigates a cooperative DMPC coupled to an automatic partitioning of the nonlinear system. The local decomposition used is based on the directed graph of the effects on control variables from the space of inputs through a successive linearization of the plant model at each sampling instant. The proposed strategy was applied to a benchmark plant and compared to centralized controller.
Anais do XX Congresso Brasileiro de Engenharia Química, 2015
Anais do XX Congresso Brasileiro de Engenharia Química, 2015
Anais do XX Congresso Brasileiro de Engenharia Química, 2015
RESUMO-As máquinas de vetores de suporte são uma poderosa ferramenta de reconhecimento de padrões... more RESUMO-As máquinas de vetores de suporte são uma poderosa ferramenta de reconhecimento de padrões. Elas representam um conjunto de metodologias do aprendizado supervisionado estatístico que é usado para classificação e análise de regressão de dados. Os vetores de suporte utilizam um hiperplano com máxima margem para separar as diferentes classes de dados. Este trabalho apresenta um sistema de detecção que utiliza as máquinas de vetores de suporte para detectar falhas em processos e realizar o diagnóstico das mesmas. A metodologia baseia-se em informações históricas quantitativas e qualitativas com máquinas de vetores de suporte treinadas e sintonizadas pelo método da evolução diferencial. O sistema de detecção de falhas foi avaliado em processos químicos para verificar a adequabilidade da proposta para a detecção e classificação de falhas com dados históricos e qualitativos. Métricas de desempenho do sistema apontam para a eficiência do sistema de detecção nos cenários investigados.
Anais do XX Congresso Brasileiro de Engenharia Química, 2015
Computer Aided Chemical Engineering, 2012
Abstract This paper presents the application of reconfigurable control strategy to a multivariabl... more Abstract This paper presents the application of reconfigurable control strategy to a multivariable neutralization process under several fault scenarios. The combined control strategy is integrated to a reconfiguration block that uses the available signals from the remaining sensors and actuators to reconstruct a signal useful to the nominal controller leading to a stable closed-loop behavior even in the presence of faults. Simulations results show that, although the overall system performance can be compromised, the reconfigurable control strategy leads to a system that is still able to operate within acceptable performance in the studied fault scenarios.
Materials Science Forum, 2012
Mathematical models for thickeners can be used for equipment design, to simulate the process oper... more Mathematical models for thickeners can be used for equipment design, to simulate the process operation, and to develop control strategies for a continuous operation. In this work, numerical simulation to obtain the final height of the sediment when operating at steady state conditions were performed using two mathematical models: the model introduced by Tiller and Chen (1988) and the one proposed by Arouca (2007). The simulated results were compared to experimental data obtained when the thickener was operated with and without the use of flocculent agent. The equipment used to obtain experimental data was a conventional thickener, built in acrylic. Aluminum sulfate was used in the experiments for the production of flocculated suspensions. The results showed that the Tiller and Chen (1988) model produced a deviation of 39.0% for kaolin suspensions and 14.3% when aluminum sulfate was added to the system. The Arouca (2007) model resulted in values much closer to those obtained experime...
labplan.ufsc.br
Page 1. CONTROLE TOLERANTE A FALHAS DE UMA COLUNA DE DESTILA¸C˜ AO Lucas Lacerda Gomes Reis ∗, Lu... more Page 1. CONTROLE TOLERANTE A FALHAS DE UMA COLUNA DE DESTILA¸C˜ AO Lucas Lacerda Gomes Reis ∗, Luıs Cláudio Oliveira-Lopes∗ ...
The interdisciplinary journal of Discontinuity, Nonlinearity, and Complexity, 2018
In this work, the variation of time and amplitude of the electrical stimulation of the heart musc... more In this work, the variation of time and amplitude of the electrical stimulation of the heart muscle is analyzed during respiratory control exercise, effect of the autonomic nervous system. The specifics are verified by recurrence plot, and recurrence quantification analysis. The analysis revealed distinguished behavior of the electrical stimulation of the heart. And, the cross recurrence between the variations of amplitude and time demonstrated the equilibrium relationship in the cardiac cycles, which are accentuated in the exercise of concentration.
posgrad.mecanica.ufu.br
... Fran Sérgio Lobato franpi22@yahoo.com.br Faculdade de Engenharia Mecânica Valder Steffen Jr v... more ... Fran Sérgio Lobato franpi22@yahoo.com.br Faculdade de Engenharia Mecânica Valder Steffen Jr vsteffen@mecanica.ufu.br Faculdade de Engenharia Mecânica ... Lobato, FS and Steffen, V., 2007, “Engineering System Design with Multi-Objective Differential Evolution”. ...
2021 14th IEEE International Conference on Industry Applications (INDUSCON), 2021
Fault detection and diagnosis in modern control systems have been of constant interest in recent ... more Fault detection and diagnosis in modern control systems have been of constant interest in recent publications. Its progress is a consequence of the requirements imposed by the development of other technologies through demands on security operations, guarantee of the required functions execution, reduction of costs, and optimization of maintenance tasks. In order to provide the survey in this area, the article discriminates the main fault detection and diagnosis techniques, allowing the reader to acquire, in different practice scenarios, an ability to discern the possibilities of applying the methods in focus. The text is divided in signal analysis-based methods, model-based methods, data-driven methods, and hybrids methods. The conclusion exposes the main global limitations in the area as possible subjects for future works.
2021 14th IEEE International Conference on Industry Applications (INDUSCON), 2021
This paper highlights the design of an adaptive observer based on radial basis function neural ne... more This paper highlights the design of an adaptive observer based on radial basis function neural network (RBFNN) for the diagnosis of actuator faults in a quadrotor UAV (Unmanned Aerial Vehicle), and the design of a fault-tolerant control system. First, the quadrotor UAV model considering the faults and unknown disturbances is presented. Next, the adaptive observer design is implemented using a reduced order model of the system, in order to simplify the structure of the neural network and consequently reduce the computational complexity and facilitate the adjustment of its parameters. The fault-tolerant control system is then exposed through the combination of the controller and the faults estimated by the adaptive observer. Simulations are performed in order to demonstrate the effectiveness of the proposed system with respect to the speed and accuracy of faults estimation with nonlinear behaviors and simultaneous occurrences in the actuators, and the attenuation of the effects of faults on the quadrotor UAV dynamics.
IEEE Latin America Transactions, 2019
Quadrotor helicopters are gaining notoriety as research platform of unmanned aerial vehicle (UAV)... more Quadrotor helicopters are gaining notoriety as research platform of unmanned aerial vehicle (UAV), due to its mechanical simplicity and high maneuverability, as well as the ability to hover and perform vertical takeoff and landing (VTOL). However, the development of control systems for such vehicles is not trivial. Quadrotors have a nonlinear and open-loop unstable behavior and they are constantly affected by aerodynamic disturbances and unmodeled dynamics. In this article, a cascade PID control strategy designed for stabilization and path tracking of an unmanned quadrotor is presented. The dynamic motion equations are obtained by the Lagrange-Euler formalism. The proposed control structure consists of an outer loop for the translational movements, followed by an inner loop for the stabilization of the quadrotor's attitude motions. Simulations and experimental results check the performance achieved with the proposed control strategy. The aircraft used is the Crazyflie 2.0 and the state estimation is accomplished through an extended Kalman filter, where information from the inertial measurement unit is fused with positional information from an ultra-wideband system.