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.

Planejamento da expansão de sistemas elétricos de distribuição considerando fatores de riscos em análise econômica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evolução cromossômica em Cassidinae sensu lato (Coleoptera, Polyphaga, Chrysomelidae)

Pós-graduação em Ciências Biológicas (Biologia Celular e Molecular) - IBRC

A variação das categorias de moda e sua influência na usabilidade e funcionalidade estudo de caso: calça masculina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação de indicadores de eficiência e racionalidade energética na produção de etanol com a aplicação da lógica fuzzy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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)

Multi-task control strategy for grid-tied inverters based on conservative power theory

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

Energy deficit does not affect immune responses of experimentally infected pacu (Piaractus mesopotamicus)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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)

Planejamento para a implantação da ISO 9001 em uma empresa do setor industrial

The fierce competitiveness of the current market and the sophistication of customer requirements made the commitment to quality a need within organizations. The search for quality has been carried out by the adoption of quality management systems, a formal organization that should be present throughout the organization, from the initial identification of market needs to the satisfaction of customer requirements. The methodology most commonly used for this purpose is based on the requirements of ISO 9001, latest version of 2008. Considering this scenario, was developed a case study in a small company of the industrial sector with the development of a plan for the implementation of ISO 9001. The proposed methodology involved the construction of a theoretical framework on the subject and the development of a case study with a qualitative approach. Initially, was applied a questionnaire to the representative of the organization about the company's operating procedures, activity logs held, current documentation, planning and resource management for the construction of an assessment about the adequacy of the company needs to ISO 9001. Were obtained as results the characterization of production processes and organizational structure of the company and examples of policy and objectives of quality, performance indicators, document control, system for visualization of non-compliances, among others. Finally, the benefits of adopting a quality management system based on ISO 9001 requirements for the company and its environmental issues such as increased process efficiency, less waste and greater profitability, were pointed out, and the conditions for effective certification in the future