An investigation of singularities in robot kinematic chains aiming at building robot calibration models for off-line programming

Robot Calibration is a term applied to the procedures used in determining actual values that describe the geometric dimensions and mechanical characteristics of a robot or multibody structure. A robot calibration system must consist of appropriate robot modeling techniques, accurate measurement equipment, and reliable model parameter determination methods. For practical improvement of a robot's absolute accuracy, error compensation methods are required that use calibration results. Important to robot calibration methods is an accurate kinematic model that has identifiable parameters. This parameterized kinematic model must be complete, continuous and minimal. This work concerns to the implementation of techniques to optimize kinematic models for robot calibration through numerical optimization of the mathematical model. The optimized model is then used to compensate the model errors in an off-line programming system, enhancing significantly the robot kinematic model accuracy. The optimized model can be constructed in an easy and straight operation, through automatic assignment of joint coordinate systems and geometric parameter to the robot links. Assignment of coordinate systems by this technique avoids model singularities that usually spoil robot calibration results

Theoretical and practical aspects of robot calibration with experimental verification

One of the greatest challenges in today's industrial robotics is the development of off-line programming systems that allow drastic reduction in robots' reprogramming time, improving productivity. The article purpose is to pave the way to the construction of generic calibration systems easily adapted to any type of robot, regardless their application, such as modular robots and robot controllers specifically designed for non-standard applications. A computer system was built for developing and implementing a calibration system that involves the joint work of computer and measurement systems. Each step of this system's development is presented together with its theoretical basis. With the development of a remote maneuvering system based on ABB S3 controller experimental tests have been carried out using an IRB2000 robot and a measurement arm (ITG ROMER) with 0.087 mm of position measurement accuracy. The robot model used by its controller was identified and the robot was calibrated and evaluated in different workspaces resulting in an average accuracy improvement from 1.5 mm to 0.3 mm

UV/Tio2 photocatalytic reactor for real textile wastewaters treatment

Textile dye wastewaters are characterized by strong colour, salts and other additives, high pH, temperature, chemical oxygen demand (COD) and biodegradable materials. Being aesthetically and environmentally unacceptable, these wastewaters need to be treated before their discharge. Anaerobic bioprocesses have been proposed as being environmentally friendly and relatively cheap; however, when applied to real effluent with a complex composition, they can fail. In this study, a photoreactor combining UV light and TiO2, immobilized in cellulosic fabric, was applied for the treatment of two industrial textile wastewaters. High colour and COD removal, and detoxification, were achieved for both wastewaters, at controlled pH of 5.5. Effluents showed very poor biodegradability due to their complex composition; thus, the proposed process is an efficient alternative

Effects of static magnetic field in Saccharomyces cerevisiae cultures under aerobic and anaerobic conditions

Magnetic fields have been studied by many researchers as an agent that provides changes in the metabolism of microorganisms. The effects in biological systems are produced by a relative movement between mobile ions or intracellular free electrons and the magnetic field, which can generate electric fields within a cell. Despite of the interaction mechanism to be yet unclear, is known also that the direct action of magnetism cause changes in the conformational shape of cell proteins, altering its functions. The purpose of this research was to investigate whether static magnetic field (SMF) could be applied to increasing ethanol yield by S. cerevisiae and verifying the biological effects on growth stimulation or inhibition. The influence of aerobic and anaerobic conditions and the ability of the cells to induce their defensive enzymes were also explored. Batch fermentations of S. cerevisiae were conducted for 26 h, in YPD medium, in hyperbaric bioreactor (Parr 4563, Parr Instruments, USA) with 5 NdFeB magnets, with an average flux of 120 mT (measured by a PHYWI Teslameter, USA). The magnets were enclosed into a transparent flat polyethylene case with 4.0 x 3.5 cm and 1.3 cm width. All magnets were disposed with the same polarity, so when closed the case every one showed similar north or south poles at each face of the case. As they repelled each one, the magnets maintained the maximal distance between them, in an “X” disposition, with a magnet in the center. Controls were performed in the same manner without magnets. To investigate the effects of gas, aerobic and anaerobic conditions trials were performed under air (1 bar and 5 bar) and nitrogen (1 bar). An increase of the cell dry weight and specific growth rate, under aerobic conditions (5 bar of total air pressure), of approximately 2-fold was obtained compared with the experiments exposed to nitrogen, for both magnetized and non-magnetized cultures. The cellular growth was not stimulated by the application of SMF. In fact, an improvement of 2-fold in specific growth rate was obtained in the control group, for aerobic and anaerobic conditions. An increase of approximately 3-fold in biomass yield was obtained in aerobic cultures compared with anaerobic. The biomass yield of exposed group to SMF was similar to non-exposed one under 5 bar of air pressure and in nitrogen cultures. On the other hand, a stimulation of ethanol production was obtained in magnetized cultures relatively to those of the controls, for both aerobic and anaerobic conditions. Generally, antioxidant enzymes were induced by total air. An increase of the SOD specific activity in magnetized cultures was obtained compared with the control experiments. Also, the SMF exposed cultures reached the highest values of the catalase specific activity. However, SMF exposure led to a decrease in the glutathione reductase activity. The marker malondialdehyde (MDA) is certainly the most widely used to assess the lipid peroxidation processes. The use of anaerobic conditions resulted in a reduction of MDA levels, for both exposed and nonexposed groups. Generally, the MDA concentration was similar for both magnetized and nonmagnetized cultures. This work shows that magnetic fields can be applied as a controlling factor of S. cerevisiae fermentations for ethanol or enzymes production

Hidrogênio eletrolítico eólico para aquecimento de ambientes

El objetivo de este trabajo es mostrar un equipo para el corte y la soldadura de metal provisto de combustible mediante hydrogen/oxygen electrolítico, así como, estudiar su optimización, utilizando un electrolisador bipolar. Se ha observado que aumentando la concentration del electrólito, el aporte neto del sistema también creció. Ya que este aumento era insignificante, fue utilizado una concentración de NaOH de 20%, con un aumento de 66%. La calidad de la soldadura, para el material ferroso, fue mejorada mediante la adición de 50% del volumen de oxígeno. Para los materiales no ferrosos esta adición no es necessária.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Hidrogênio eletrolítico eólico para aquecimento de ambientes

El objetivo de este trabajo es mostrar un equipo para el corte y la soldadura de metal provisto de combustible mediante hydrogen/oxygen electrolítico, así como, estudiar su optimización, utilizando un electrolisador bipolar. Se ha observado que aumentando la concentration del electrólito, el aporte neto del sistema también creció. Ya que este aumento era insignificante, fue utilizado una concentración de NaOH de 20%, con un aumento de 66%. La calidad de la soldadura, para el material ferroso, fue mejorada mediante la adición de 50% del volumen de oxígeno. Para los materiales no ferrosos esta adición no es necessária.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Geração, tratamento e disposição final dos resíduos das estações de tratamento de água do estado de Pernambuco

This article deals with the generation, quantification and final disposal of the sludge generated at existing Water Treatment Plants (WTPs), operating in the state of Pernambuco. The research was carried out in the period between January 2015 and December 2016 by the collection, systematization and interpretation of data that showed 246 WTPs that generate residues, of which 69 in decanters and filters, 176 only in the filters and one in the desalination system. The largest number of conventional WTPs is in the metropolitan region of Recife and the highest production of sludge was observed in the Capibaribe river basin, which receives a load of between 50 and 50,000 kg / (m3day). It was verified that approximately 75% of the states WTPs discard their residues in water bodies and 22% in the soil, without any kind of treatment. Only 3% perform the degassing process, yet discarding the solid mass in the soil, without any control at the final disposal of the same.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Universidade Federal Rural de Pernambuco (UFRPE), Universidade Federal de Pernambuco (UFPE), COMPESA, ARPEinfo:eu-repo/semantics/publishedVersio

Utilização do processamento digital de imagens no monitoramento de estações de tratamento de efluentes

Neste trabalho é proposto um procedimento para reconhecimento semi-automático das espécies de protozoários por análise de imagem. Este programa (ProtoRec v.2) foi em seguida utilizado para estudar a evolução da microfauna durante períodos de transição (paragem e arranque da estação). Os resultados obtidos foram satisfatórios em relação ao reconhecimento das espécies pelo programa e o acompanhamento da estação permitiu-nos verificar a degradação e envelhecimento da lama e o aparecimento de protozoários que evidenciam tal fato

Survey of a wastewater treatment plant microfauna by image analysis

The microfauna present in the activated sludge of a wastewater treatment plant is mainly composed by bacteria, protozoa and metazoa. The protozoan species are quite sensitive to physical, chemical and operational processes making them, thus, precious indicators of the state of the plant. Several authors already established relationships between the predominance of certain species or group and some parameters of the plant, such as the biotic indices namely the Sludge Biotic Index. All the above-mentioned procedures demand the identification, classification and quantification of the different species. Normally this is done manually, which implies both time and expertise. In the present work a semi-automatic protozoan recognition procedure by means of image analysis is attempted. The program built for this purpose (ProtoRec v.3) was also used to study the evolution of the microfauna during transient operation times (stoppage and re-run). The results were rather satisfactory in terms of protozoa recognition and the survey of the transient phase allowed verifying the aging and degradation of the microfauna by means of the different predominant species

Estudo por Análise de Imagem do Comportamento de uma Estação de Tratamento de Efluentes sob Condições Transientes

A microfauna presente numa estação de tratamento de efluentes por lamas activadas é composta essencialmente por bactérias, protozoários e metazoários. Os protozoários apresentam uma sensibilidade aos fenómenos físico-químicos e operacionais que os tornam indicadores do estado de funcionamento da estação. A literatura apresenta relações entre a abundância de uma certa espécie ou grupo e parâmetros da estação. Uma outra possibilidade é a qualificação do estado da ETAR através de índices bióticos como o SBI. Todos estes procedimentos exigem uma identificação, classificação e quantificação das espécies presentes. Geralmente isto é feito manualmente, o que implica tempo e muitas vezes a presença de um técnico especializado. Neste trabalho é proposto um procedimento para reconhecimento semi-automático das espécies de protozoários por análise de imagem. Este programa (ProtoRec v.2) foi em seguida utilizado para estudar a evolução da microfauna durante períodos de transição (paragem e arranque da estação). Os resultados obtidos foram satisfatórios em relação ao reconhecimento das espécies pelo programa e o acompanhamento da estação permitiu-nos verificar a degradação e envelhecimento da lama e o aparecimento de protozoários que evidenciam tal facto