A special experimental setup working on the stylus probe LVDT principle has been designed and developed to determine the surface roughness with a fair amount of accuracy.
High pressure (HP) processing is an innovative process for food preservation mainly due the inactivation that pressure induces in microorganisms and/or enzymes. The correct design and optimization of HP processes requires knowledge of the... more
High pressure (HP) processing is an innovative process for food preservation mainly due the inactivation that pressure induces in microorganisms and/or enzymes. The correct design and optimization of HP processes requires knowledge of the volumetric properties of the foods and pressure fluids implicated in those processes. In this study, a cell capable of measuring volume variations caused by pressure and/or
In this paper a micropositioning mechatronics system is conceived and described. Its mechanical design is optimized in order to achieve high precision displacements. High speed closed-loop feedback control is obtained by using both PID... more
In this paper a micropositioning mechatronics system is conceived and described. Its mechanical design is optimized in order to achieve high precision displacements. High speed closed-loop feedback control is obtained by using both PID and ramp control algorithms programmed as virtual instruments (VI) on an FPGA (Field Programmable Gate Array) module. User controls are programmed in an independent Host VI. A Linear Variable Differential Transformer (LVDT) is employed as a position feedback sensor, while positioning accuracy and repeatability are experimentally assessed by using a Michelson-type laser Doppler interferometric system. Different experiments with point-to-point positioning are conducted. In the first set of experiments, positioning with 100 μm steps is performed. In a second step, 10 mm positioning experiments are done. The system shows a marked nonlinearity when longer positioning steps are used; this nonlinearity influences significantly the output error. It is hence f...
Aiming for teaching/learning support in sciences and engineering areas, the Remote Experimentation concept (an E-learning subset) has grown in last years with the development of several infrastructures that enable doing practical... more
Aiming for teaching/learning support in sciences and engineering areas, the Remote Experimentation concept (an E-learning subset) has grown in last years with the development of several infrastructures that enable doing practical experiments from anywhere and anytime, using a simple PC connected to the Internet. Nevertheless, given its valuable contribution to the teaching/learning process, the development of more infrastructures should continue, in order to make available more solutions able to improve courseware contents and motivate students for learning. The work presented in this paper contributes for that purpose, in the specific area of industrial automation. After a brief introduction to the Remote Experimentation concept, we describe a remote accessible lab infrastructure that enables users to conduct real experiments with an important and widely used transducer in industrial automation, named Linear Variable Differential Transformer.
The need of recording data and collect measurements taken by sensors is common to many applications and aims to facilitate the registration and monitoring of the development of events in various areas such as health, industry,... more
The need of recording data and collect measurements taken by sensors is common to many applications and aims to facilitate the registration and monitoring of the development of events in various areas such as health, industry, meteorology, precision agriculture and others. However the electrical signals provided by sensors are not always directly capable of being manipulated which implies the need for adequacy of these signals so that they can be used in monitoring systems (data logger). In precision agriculture or phytomonitoring one of the sensors used for studies is designated as LVDT (Linear Variable Differential Transformer), which due to its characteristics require a signal processing system to facilitate its use. Thus this study aimed to demonstrate the development of an adequacy system of electrical signal to be used connected to a LVDT and to a data logger and thus provide the monitoring of crop development. The results showed that the system deals properly the signals repr...
In this paper a micropositioning mechatronics system is conceived and described. Its mechanical design is optimized in order to achieve high precision displacements. High speed closed-loop feedback control is obtained by using both PID... more
In this paper a micropositioning mechatronics system is conceived and described. Its mechanical design is optimized in order to achieve high precision displacements. High speed closed-loop feedback control is obtained by using both PID and ramp control algorithms programmed as virtual instruments (VI) on an FPGA (Field Programmable Gate Array) module. User controls are programmed in an independent Host VI. A Linear Variable Differential Transformer (LVDT) is employed as a position feedback sensor, while positioning accuracy and repeatability are experimentally assessed by using a Michelson-type laser Doppler interferometric system. Different experiments with point-to-point positioning are conducted. In the first set of experiments, positioning with 100 μm steps is performed. In a second step, 10 mm positioning experiments are done. The system shows a marked nonlinearity when longer positioning steps are used; this nonlinearity influences significantly the output error. It is hence f...
