Active vibration control using delayed resonant feedback

Delayed feedback (DF) control is a well-established technique to suppress single frequency vibration of a non-minimum phase system. Modal control is also a well-established technique to control multiple vibration modes of a minimum phase system. In this paper these techniques are combined to simultaneously suppress multiple vibration modes of a non-minimum phase system involving a small time delay. The control approach is called delayed resonant feedback (DRF) where each modal controller consists of a modal filter to extract the target mode signal from the vibration response, and a phase compensator to account for the phase delay of the mode. The methodology is first discussed using a single mode system. A multi-mode system is then studied and experimental results are presented to demonstrate the efficacy of the control approach for two modes of a beam. It is shown that the system behaves as if each mode under control has a dynamic vibration absorber attached to it, even though the actuator and the sensor are not collocated and there is a time delay in the control system. © 2013 IOP Publishing Ltd.

Mini-inversores para aproveitamento de energia fotovoltaica, com técnicas de MPPT, sincronismo e conexão com a rede de CA em BT, proteção de ilhamento, gerenciamento da energia e da operação

Pós-graduação em Engenharia Elétrica - FEIS

Estudo da comunicação de um compensador série para rede de distribuição com o centro de controle utilizando tecnologia GPRS

Pós-graduação em Engenharia Elétrica - FEIS

Controle da injeção de potências ativa e reativa em inversor de Geração Distribuída conectado à rede de distribuição em corrente alternada em baixa tensão, empregando LMIs com realimentação de estados e critérios de D-estabilidade

Pós-graduação em Engenharia Elétrica - FEIS

MODEL-BASED COMPENSATION FOR BURST MESSAGE LOSS IN WIRELESS NETWORKED CONTROL SYSTEMS: EXPERIMENTAL RESULTS

A recent trend in networked control systems (NCSs) is the use of wireless networks enabling interoperability between existing wired and wireless systems. One of the major challenges in these wireless NCSs (WNCSs) is to overcome the impact of the message loss that degrades the performance and stability of these systems. Moreover, this impact is greater when dealing with burst or successive message losses. This paper discusses and presents the experimental results of a compensation strategy to deal with this burst message loss problem in which a NCS mathematical model runs in parallel with the physical process, providing sensor virtual data in case of packet losses. Running in real-time inside the controller, the mathematical model is updated online with real control signals sent to the actuator, which provides better reliability for the estimated sensor feedback (virtual data) transmitted to the controller each time a message loss occurs. In order to verify the advantages of applying this model-based compensation strategy for burst message losses in WNCSs, the control performance of a motor control system using CAN and ZigBee networks is analyzed. Experimental results led to the conclusion that the developed compensation strategy provided robustness and could maintain the control performance of the WNCS against different message loss scenarios.

Tm-afm nonlinear motion control with robustness analysis to parametric errors in the control signal determination

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Control of Limit Cycle Oscillation in a Three Degrees of Freedom Airfoil Section Using Fuzzy Takagi-Sugeno Modeling

This work presents a strategy to control nonlinear responses of aeroelastic systems with control surface freeplay. The proposed methodology is developed for the three degrees of freedom typical section airfoil considering aerodynamic forces from Theodorsen's theory. The mathematical model is written in the state space representation using rational function approximation to write the aerodynamic forces in time domain. The control system is designed using the fuzzy Takagi-Sugeno modeling to compute a feedback control gain. It useds Lyapunov's stability function and linear matrix inequalities (LMIs) to solve a convex optimization problem. Time simulations with different initial conditions are performed using a modified Runge-Kutta algorithm to compare the system with and without control forces. It is shown that this approach can compute linear control gain able to stabilize aeroelastic systems with discontinuous nonlinearities.

Demonstration of non-collocated vibration control of a flexible manipulator using electrical dynamic absorbers

This paper describes an experimental study into the vibration control of a servo system comprising a servo motor and a flexible manipulator. Two modes of the system are controlled by using the servo motor and an accelerometer attached to the tip of the flexible manipulator. The control system is thus non-collocated. It consists of two electrical dynamic absorbers, each of which consists of a modal filter and, in case of an out-of-phase mode, a phase inverter. The experimental results show that each absorber acts as a mechanical dynamic vibration absorber attached to each mode and significantly reduces the settling time for the system response to a step input.

Nonlinear control in an electromechanical transducer with chaotic behaviour

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

SDRE control strategy applied to a nonlinear robotic including drive motor

A robotic control design considering all the inherent nonlinearities of the robot-engine configuration is developed. The interactions between the robot and joint motor drive mechanism are considered. The proposed control combines two strategies, one feedforward control in order to maintain the system in the desired coordinate, and feedback control system to take the system into a desired coordinate. The feedback control is obtained using State-Dependent Riccati Equation (SDRE). For link positioning two cases are considered. Case I: For control positioning, it is only used motor voltage; Case II: For control positioning, it is used both motor voltage and torque between the links. Simulation results, including parametric uncertainties in control shows the feasibility of the proposed control for the considered system.

Nonlinear angle control of a sectioned airfoil by using shape memory alloys

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estratégia de controle multifuncional para sistemas fotovoltaicos de geração de energia elétrica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nonlinear state estimation and control applied to a manipulator robotic including drive motor

A robotic control design considering all the inherent nonlinearities of the robot engine configuration is developed. The interactions between the robot and joint motor drive mechanism are considered. The proposed control combines two strategies, one feedforward control in order to maintain the system in the desired coordinate, and feedback control system to take the system into a desired coordinate. The feedback control is obtained using State Dependent Riccati Equation (SDRE). For link positioning two cases are considered. Case 1: For control positioning, it is only used motor voltage; Case 2: For control positioning, it is used both motor voltage and torque between the links. Simulation results, including parametric uncertainties in control shows the feasibility of the proposed control for the considered system.

Segurança das condições de aplicação de herbicidas com aerobarco em plantas daninhas aquáticas no lago da Hidrelétrica de Jupiá

Os objetivos deste trabalho foram quantificar as exposições dérmicas (EDs) e respiratórias (ERs) proporcionadas ao piloto e ao seu ajudante nas aplicações de herbicidas para o controle de plantas daninhas aquáticas com aerobarco; classificar essas condições de trabalho em seguras ou inseguras; e calcular a necessidade de controle das exposições (NCE) e o tempo de trabalho seguro (TTS). O aerobarco utilizado tinha casco de alumínio (4,85 x 2,42 m) e acionamento por hélice acoplada a motor a gasolina de 350 HP. O equipamento de pulverização era composto por bomba de diafragma com fluxo máximo de 49,69 L min-1, pressão máxima de 25 kg cm-2, acionada por motor a gasolina de 4 HP, e tanque de calda de 189 L. A barra de pulverização de alumínio era composta de duas seções laterais de 3 m, posicionadas na linha entre o encosto do banco do piloto e o início da estrutura protetora da hélice. Cada seção da barra tinha seis bicos com pontas de jato plano com indução de ar AI 100 03, espaçados de 0,5 m, e uma ponta OC 20 fixada em cada extremidade. O conjunto de pontas pulverizava faixas de 6 m de largura e aplicava o volume de calda de 200 L ha-1. O sistema tinha gerenciador de fluxo, controlado por central eletrônica acoplada a DGPS (com precisão submétrica), para corrigir automaticamente a vazão em função de alterações na velocidade real da embarcação. As EDs e ERs aos herbicidas foram calculadas com os dados substitutos das exposições às caldas, avaliadas com os traçadores cobre e manganês adicionados às caldas. As exposições foram extrapoladas para uma jornada de trabalho de seis horas. A segurança das condições de trabalho foi determinada com o cálculo da margem de segurança (MS), utilizando-se a fórmula MS = (NOEL x 70)/(QAE x 10), em que QAE = quantidade absorvível da exposição. As condições de trabalho foram classificadas em seguras, se MS>1, ou inseguras, se MS<1. As exposições proporcionadas pelas condições de trabalho foram de 10,65 mL de calda por dia para o piloto e de 16,80 mL por dia para o ajudante, que fica sentado em uma cadeira a 2,0 m à frente do piloto e da barra de pulverização. Classificaram-se como seguras as aplicações dos herbicidas glyphosate (Rodeo, 6 L ha-1), 2,4D (DMA 806 BR, 8 L ha-1) e fluridone (Sonar AQ, 0,4 L ha-1), para o piloto e o seu ajudante. Classificou-se como insegura a aplicação do herbicida diquat (Reward, 4,0 L ha-1) para as duas condições de trabalho, cujas necessidades de controle das exposições calculadas foram de 65% para o piloto e de 78% para o ajudante do piloto.

Alternative procedure for the cold test for soybean seeds

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)