Celiane Costa Machado

Adaptive Neuro-Fuzzy Friction Compensation Mechanism to Robotic Actuators

This paper presents a non-linear friction compensation mechanism using a combination of neural network (NN) with fuzzy system (neuro-fuzzy compensator), applied to harmonic-drive robotic actuators. The friction compensation torque is constituted by NN output, which is trained off-line. Since the friction changes significantly over time, temperature and equipment operational conditions, the NN loses its performance. To recover this performance, a fuzzy algorithm is proposed to deal with the variation friction parameters. The output of the fuzzy algorithm is a gain that multiplied by the NN output will adjust the friction compensation torque. Experimental results have shown the efficiency of the proposed mechanism.

Um novo algoritmo para a modelagem dinâmica de manipuladores flexíveis

Active control law development of flexible structures is still an open problem. It has been the object of many researches, mainly starting from the eighties. In spite of many works dedicated to the dynamic modeling of such structures, the obtaining of a realistic dynamic model is of fundamental importance for the control law development. In the present work it is introduced a new algorithm to determinate in a quite simple way, the dynamic differential equations of a one flexible link manipulator. It is still developed analytic transfer functions for this specific problem, which are important for the validation of the lumped mass approach model proposed in the form of an algorithm.

Percepções de docentes sobre as mudanças curriculares do Ensino Médio no Brasil

O presente artigo apresenta os resultados de uma pesquisa de abordagem qualitativa, realizada com docentes do Ensino Medio, sobre suas percepcoes e vivencias em relacao ao contexto de mudancas curriculares iniciadas na decada de 1990, com a reforma do Ensino Medio. Para tal estudo foram realizadas entrevistas semiestruturadas com dez professores atuantes na rede publica e/ou privada da cidade de Rio Grande, estado do Rio Grande do Sul. Os resultados obtidos mostram as dificuldades enfrentadas na implementacao das mudancas e apontam a necessidade de modificacoes estruturais do sistema escolar, valorizacao da profissao de magisterio e aprimoramento na formacao docente. Com este estudo espera-se contribuir para as discussoes sobre as mudancas do Ensino Medio no atual cenario educacional brasileiro.

Práticas docentes atualizadas na ecologia digital

ensinar e que esse processo e vivenciado pelos professores no dia a dia do espaco escolar. Assim, a insercao de dispositivos eletronicos digitais pessoais na sala de aula impulsionou essa investigacao, que objetiva compreender como os professores da Educacao Basica atualizam sua pratica docente ao trabalhar na ecologia digital com esses dispositivos. Como estrategia metodologica, analisou-se as narrativas de professores da rede publica de ensino ingressantes na ecologia digital. Tais narrativas foram desencadeadas pela seguinte questao: Como preparas e ministras as tuas aulas apos tua insercao no projeto Um Computador por Aluno? Na analise das narrativas, identificaram-se algumas mudancas na rotina dos professores. Porem, para alcancarmos uma atualizacao do fazer pedagogico e a efetivacao desse fazer e necessario uma formacao pautada no vivenciar e no experienciar do professor, enquanto sujeito que, no seu fazer, produz conhecimento.

Active Control of Flexible Structures Submitted to Incompressible Flows

This work presents a survey on the control law development to actively attenuate the vibrations of a flexible structure submitted to fluid flow. Firstly, a robust controller with LQG/LTR approach was developed. Numerical tests were carried out being robustness characteristics to flow induced vibration and to noise rejection verified, for the case of equal nominal and real plants. The same robustness was not verified, when parametric variations were introduced. Therefore, another controller, based on regulator and filter pole placement approach, was developed where the direct loop obeys stability and performance robustness criterions, allowing to obtain good numerical results, even in the presence of significant parametric variations.Copyright