An evolutionary approach for the motion planning of redundant and hyper-redundant manipulators

The trajectory planning of redundant robots is an important area of research and efficient optimization algorithms are needed. The pseudoinverse control is not repeatable, causing drift in joint space which is undesirable for physical control. This paper presents a new technique that combines the closed-loop pseudoinverse method with genetic algorithms, leading to an optimization criterion for repeatable control of redundant manipulators, and avoiding the joint angle drift problem. Computer simulations performed based on redundant and hyper-redundant planar manipulators show that, when the end-effector traces a closed path in the workspace, the robot returns to its initial configuration. The solution is repeatable for a workspace with and without obstacles in the sense that, after executing several cycles, the initial and final states of the manipulator are very close

An evolutionary approach to the trajectory planning of redundant robots

Several kinematic techniques for the trajectory optimization of redundant manipulators control the gripper using the pseudoinverse of the Jacobian. Nevertheless, these algorithms lead to a kind of chaotic motion with unpredictable arm configurations. This paper presents a new technique for solving the inverse kinematics problem for redundant manipulators that combines the closed-loop pseudoinverse method with genetic algorithms.N/

Assimilação de metabólitos secundários do milho em adultos de Spodoptera frugiperda.

Poster

Admittance spectroscopy of Cu2ZnSnS4 based thin film solar cells

In this report, we propose an AC response equivalent circuit model to describe the admittance measurements of Cu2ZnSnS4 thin film solar cell grown by sulphurization of stacked metallic precursors. This circuit describes the contact resistances, the back contact, and the heterojunction with two trap levels. The study of the back contact resistance allowed the estimation of a back contact barrier of 246 meV. The analysis of the trap series with varying temperature revealed defect activation energies of 45 meV and 113 meV. The solar cell’s electrical parameters were obtained from the J-V curve: conversion efficiency, 1.21%; fill factor, 50%; open circuit voltage, 360 mV; and short circuit current density, 6.8 mA/cm2

Implicação do ácido salicílico na indução de compostos de defesa no controle da ferrugem asiática da soja.

Poster

Induced response of soybeans to phakopsora pachyrhizi inoculation and alternativa products used in organic production system.

Alternative products for soybean Asian rust (Phakopsora pachyrhizi) management in organic production system were tested. Among them, calda viçosa (CV, mixture of Cu, Zn and Mg sulfates), Fish Fertil" (FF, hydrolyzed organic based on crustacean shell and marine fish, rich in chitosan), and sodium silicate (55) were selected for defense induction studies. Sovbean sown in greenhouse, at V3 development stage, was sprayed with alternative products and inoculated or not-inoculated with spores of P. pachyrhizi. Control plants were neither sprayed with products nor fungus inoculated. At O (before treatment) and 72, 96 and 120 hours after treatments, leaves were collected, extracted in MeOH, filtered, and HPLC injected for identification and quantification of compounds. In general, FF + fungus plant treated increased isoflavone concentrations and responded faster than the other treatments. Malonyl genistin, malonyl daidzin and malonyl glycitin concentrations of were approximately, four and 90 times (72h) and two (96h) times greater, respectively, compared to previous analysis, in fungus + FF treated plants. In this treatment, genistein and daidzein concentration also increased at 72h after treatment. Acethyl daidzin concentration increased in most of treatments, but was bigger in FF + fungus, 72h after treatment. Aglycones (genistein, daidzein and glycitein) concentration was lower compared to glycosides. However, FF has been exhaustively tested for management of phytopathogens in flowers and fruits, its role in soybean disease management needs additional experiments. Thus, for further elucidation P. pachyrhizi management by using FF,tests with pure chitosan is the next step of our studies

Do different casein concentrations increase the adverse effect of rutin on the biology of Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae)?

The flavonoid rutin is recognized as playing an important role in the protection of plants against lepidopterans. Bioassays with this compound are generally carried out using artificial diets. Proteins of high energy value, such as casein, are important ingredients of insect artificial diets as a source of essential amino acids. However, such proteins can generally increase the allelochemical activity. Our objective was to evaluate the effects of rutin on larvae of the velvetbean caterpillar Anticarsia gemmatalis Hübner by incorporating this allelochemical into diets with different concentrations of casein. Three casein concentrations (0, 7 g, or 14 g) combined with none, 0.65%, or 1.30% of rutin were added to the rearing diet and offered to the larvae from hatching to pupation. Rutin negatively affected larval development, the amount of food consumed, and pupal weight of A. gemmatalis. These negative effects were clearly seen in insects fed on diets with 7 g of casein to which any concentration of rutin was added. The effects of rutin when added to the diets without casein were stronger than in diets containing a suitable amount of casein (14 g). The greater negative effects of rutin in diets containing suboptimal concentrations of casein indicate that casein can increase the effects of rutin only when the diets are nutritionally unsuitable for insect development

Trajectory planning of redundant manipulators using genetic algorithms

The trajectory planning of redundant robots is an important area of research and efficient optimization algorithms are needed. This paper presents a new technique that combines the closed-loop pseudoinverse method with genetic algorithms. The results are compared with a genetic algorithm that adopts the direct kinematics. In both cases the trajectory planning is formulated as an optimization problem with constraints