Robust controller design of a wheelchair mobile via LMI approach to SPR systems with feedback output

This article discusses the design of robust controller applied to Wheelchair Furniture via Linear Matrix Inequalities (LMI), to obtain Strictly Positive Real (SPR) systems. The contributions of this work were the choice of a mathematical model for wheelchair: mobile with uncertainty about the position of the center of gravity (CG), the decoupling of the kinematic and dynamical systems, linearization of the models, the headquarters building of parametric uncertainties, the proposal of the control loop and control law with a specified decay rate.

The use of nonlinear programming as a tool for maximum profit feed formulation of broilers

The purpose of this study was to compare linear and nonlinear programming models for feed formulation, for maximum profit, considering the real variation in the prices of the corn, soybean meal and broilers during the period from January of 2008 to October of 2009, in the São Paulo State, Brazil. For the nonlinear formulation model, it was considered the following scenarios of prices: a) the minimum broiler price and the maximum prices of the corn and soybean meal during the period, b) the mean prices of the broiler, corn and soybean meal in the period and c) the maximum broiler price and the minimum prices of the corn and soybean meal, in the considered period; while for the linear formulation model, it was considered just the prices of the corn and the soybean. It was used the Practical Program for Feed Formulation 2.0 for the diets establishment. A total of 300 Cobb male chicks were randomly assigned to the 4 dietary treatments with 5 replicate pens of 15 chicks each. The birds were fed with a starter diet until 21 d and a grower diet from 22 to 42 d of age, and they had ad libitum access to feed and water, on floor with wood shavings as litter. The broilers were raised in an environmentally-controlled house. Body weight, body weight gain, feed intake, feed conversion ratio and profitability (related to the prices variation of the broilers and ingredients) were obtained at 42 d of age. It was found that the broilers fed with the diet formulated with the linear model presented the lowest feed intake and feed conversion ratio as compared with the broilers fed with diets from nonlinear formulation models. There were no significant differences in body weight and body weight gain among the treatments. Nevertheless, the profitabilities of the diets from the nonlinear model were significantly higher than that one from the linear formulation model, when the corn and soybean meal prices were near or below their average values for the studied period, for any broiler chicken price.

Desenvolvimento de um sistema de controle para avaliação de fontes de energias renováveis no bombeamento de água

The use of alternative energy systems in the current days is an urgent necessity due to the problems that the planet is facing as the heating and loss of ozone layer. The scarcity of conventional energy is another problem that must be solved for the future of humanity. It must be considered that the people are inhabiting places moved away not always with available energy. The application of technologies as automation and control can help us to solve this problem. Therefore, this work aimed at apply an equipment of industrial usage, the Programmable Logical Controller, PLC, in alternative energies systems, as eolic generation and fotovoltaic generation used for water pumping, aiming the automatic control and the efficiency in the places where it has simultaneous availability of these sources, based in criterion of priority that previously established itself between them. It was made a hydraulic and energetic evaluation of the energy system, eolic and fotovoltaic, used in the automatic control system of pumping, in the place of accomplishment of the experiment, according to previously established physical conditions. The results have shown that the control system using the PLC is practicable and has trustworthiness. The program developed can be adapted for the use with several power plants in a specific application place. The fotovoltaic system of pumping, using a polycrystalline of 70 Watts connected to a pump Shurflo 8000, showed to be efficient with significant flows in almost all the months. The eolic system of pumping, using an eolic generator of 400 Watts assembled in place of experiment, did not demonstrate energetic capacity for use in this specific type of application.

Análise de sistemas de proteção por redundância e bloqueio de energias contra acidentes em prensas e equipamentos rotativos

This monograph presents the main objective of analyzing the redundancy protection systems of protection for redundancy and block of energies against accident in presses and rotating equipment. After understanding two specific goals, on this case, show the systems of protection against accidents in rotating equipments, presses and similar; and discuss the vulnerabilities of current systems of protection against accidents in presses and similar, we will propose a system of autonomous redundancy of Programmable Logic Controller (PLC) operating simultaneously taking online in the event of failure of one of the two. The methodology was worked through a revision of a variety of bibliography, and interpretation of national and international standards as well as access to research on systems, practices used in industrial and companies supplying products and of companies and energy blockages solutions