Sensors and Actuators


LipoTool - Mechanical design of a new Calliper

LipoTool

Leader: Maria Teresa Restivo
UISPA Team: Manuel Rodrigues Quintas, Tiago Andrade, Carlos Moreira da Silva and Teresa Amaral
Period: 2010

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The existing calipers have experienced insufficient progress, suffering of different limitations and shortcomings, namely inconsistency in the data collecting process and in mechanical characteristics.

The main goal of this project is to study and to develop a novel mechanical design distinct from those available in the market. It uses a constant force actuator within the housing handle, which imposes a constant contact pressure between the end tip faces and the skinfold under measurement. It also offers an opening limit increase of the end tips. Electronic and mechanical features make it able of performing dynamic measurements during tissues compressibility. The device prototype was calibrated at reference laboratory and evaluated in a health environment under UPorto protocol.

This novelty justifies a patent submissions at National and International levels and has been also the reason for two awards in 2010 – 1st place Innovation in Nutrition Awards 2010 and FEUP Colheita 75.

Cooperation: FCNAUP - Faculty of Nutrition of University of Porto; FADEUP - Faculty of Sport of University of Porto; CATIM - Technological Center for Metal Industry

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LipoTool 2011 (Adipsmeter v4 + Liposoft 2011)

video about lipotool

Portable servopneumatic device

Portable Servopneumatic Device

Leader: Fernando Gomes de Almeida
UISPA Team: João Falcão Carneiro
Period: From 2010 to 2011

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This prototype was developed to demonstrate the potentialities achieved with the nonlinear control laws developed at UISPA. The system is composed by standard pneumatic components and has the ability to perform positioning tasks with an error of ±1µm (the encoder resolution), with any mass ranging from 2kg to 13kg in any arbitrary position of the cylinder stroke.

Optical fibre pressure sensors for small scale studies of groundwater flow

Leader: José Luís Santos
UISPA Team: Maria Teresa Restivo
Period: From 2009 to 2010

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The project was funded by Universidade do Porto Rectory and Banco Santander Totta, Sept. 2009/August 2010. It has been a multidisciplinary project also including students from physics department at the faculty of sciences and from civil and mechanical departments at the faculty of engineering both from University of Porto.

The underground movement of water through soil and rock is an important phenomenon in Civil Engineering. Small scale prototypes are used for studies, where several layouts of soil and water in steady state/transient conditions can be studied in detail. A water tank prototype was built with a reflective optical fibre pressure sensor based on a GRIN lens and a mirror. The mirror is connected to an elastic membrane that is deformed when water pressure is applied and the lens is correctly aligned with the mirror and fixed. The distance between the mirror and the lens changes, so the reflective optical power changes as well and it is directly proportional to the water pressure inside the tank.

Optical fibre pressure sensors for small scale studies of groundwater flow

SeepTool – Small scale studies of groundwater flow

Leader: José Couto Marques
UISPA Team: Maria Teresa Restivo
Period: From 2009 to 2010

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The project was funded by Universidade do Porto Rectory and Banco Santander Totta, September 2009 / August 2010. It has been a multidisciplinary project also including students and researchers from civil and mechanical departments at the Faculty of Engineering and physics department from Faculty of Sciences both from University of Porto. Groundwater flow or seepage, the underground movement of water through soil and rock, is a physical phenomenon of great importance to Civil Engineering, which is usually covered in introductory Soil Mechanics courses. Students tend to have some difficulty in mastering the basic concepts, mostly due to their lack of feeling for the underlying physics. This has provided the motivation for the development of an experimental tool for small scale studies of seepage.

Raceways – A hyperintensive fish farming concept for lasting competitiveness and superior production

Raceways

Leader: Maria Teresa Borges
UISPA Team: Maria Teresa Restivo and Joaquim Gabriel
Period: 2008

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The project task leader Maria Teresa Borges was within Centro Interdisciplinar de Investigação Marinha e Ambiental CIIMAR, EC-CRAFT/016869/2006. This Project finished in June 2008.

Cost-effective manner aquaculture fish production systems must be capable of maintaining proper levels of water quality (WQ) parameters like temperature, dissolved oxygen, pH, un-ionized ammonia, nitrite and carbon dioxide. In intensive recirculation aquaculture systems the operator response time is very short and so it imposes accurate real-time information for critical water quality parameters, reliable alarm and backup systems. An on-line water quality monitoring system prototype was developed for the supervision of a laboratory shallow-raceway hyperintensive aquaculture model with 7 cm water height per tank, three tanks in series and a water recycling system.

The monitored parameters include water level, recirculation flow, oxygen, temperature, pH, ORP and CO2 logged in a Microsoft Access database. The software application was developed in LabVIEW 8.5 for the supervision of a laboratory shallow-raceway hyperintensive aquaculture model. The used sensorization was available in the market.

Evaluation of % of Body fat

Leader: Maria Teresa Restivo
UISPA Team: Teresa Amaral, Fátima Chouzal and Manuel Rodrigues Quintas
Period: 2008

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The Project has attributed a grant to a student for working in the development of a skinfold calliper and has been funded by Fresénius Kabi Pharma Portugal Lda, http://www.fresenius-kabi.com/. It has been contributing for the development of the prototype LipoStoft 2008.

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Development of a Hand Grip Dynamometer for Nutritional Assessment

Leader: Manuel Rodrigues Quintas
UISPA Team: Carlos Moreira da Silva, Teresa Amaral, Maria Teresa Restivo, Fátima Chouzal
Period: From 2007 to 2008

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The project was funded by Universidade do Porto Rectory and Caixa Geral de Depósitos, Sept. 2007/August 2008. It has been a multidisciplinary project also including students and researchers from mechanical engineering department, from Faculty of Nutrition and Food Science and from Faculty of Sports.

The measurement of the hand grip strength of individuals can be used as nutritional assessment technique and has been shown to be a reliable screening tool for undernutrition. Several apparatus, mainly addressed to sports area, present some setbacks when applied to groups with severe nutritional problems or/and to elderly people: they are heavy, uncomfortable and manly they do not have the capability to discriminate between grip force measurements in the lower limit of measurement range. To solve this problem it's necessary to develop a sensor device capable of measuring in a wide range of values; Low/No maintenance - The health care environment where the HG devices will be used is not suitable for frequent maintenance or calibration, which implies a robust design of the sensing system as well as the complementary electronics involved; Low cost - The commercially available HG devices don't correspond to the aims previously determined and have also the disadvantage of being very expensive. This represents an obstacle to their applicability as a screening method in the clinical setting. For this reason, a low cost solution must be an imperative objective to be present at the different phases of the development.

Cooperation: FCNAUP - Faculty of Nutrition of University of Porto.

Virtual instrumentation for monitoring, digital recording and assessing body composition

Adipsmeter v0

Leader: Maria Teresa Restivo
UISPA Team: Joaquim Gabriel, Teresa Amaral, Fátima Chouzal and Manuel Rodrigues Quintas
Period: From 2007 to 2008

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The project was funded by Universidade do Porto Rectory and Caixa Geral de Depósitos, Sept. 2007/August 2008. It has been a multidisciplinary project also including students and researchers from mechanical engineering department, from Faculty of Nutrition and Food Science and from Faculty of Sports. The project output has been the first sensorized skinfold caliper communicating by wireless protocol (ZigBee) with a software application integrating a database. The project was awarded in 2009 and got a patent in December 2009 (PT nº 103 721).

Cooperation: FCNAUP - Faculty of Nutrition of University of Porto; FADEUP - Faculty of Sport of University of Porto; SINERGIMO - Management Consultants, Lda.

LipoTool 2008

video about the lipotool 2008

INSPECT - Filled bottles inspection

INSPECT

Leader: Joaquim Gabriel Mendes
UISPA Team: Maria Teresa Restivo
Period: From 2006/01/08 to 2008/03/30

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The inspection of the filled bottles in order to the detect the presence of foreigner objects is a fundamental operation to guarantee the quality in the production of drinks.

However, while the inspection of empty bottles is possible through the use of commercial equipment based on automatic real-time video analysis, for the inspection of filled bottles still there is no equipment in the market able to execute this task efectively and safely.

The reflection and diffraction phenomena of the light in the passage through the glass of the bottle, as well as, its content, the variation of the intensity of the ambient light, the large speed of the production lines, the natural turbulence of the liquid, the foam and the liquid drops on the outside wall of the bottle, the scratches and defects of the glass are some of the difficulties to be overcome.

Since this a problem of all the companies that produce drinks, the successful development of an equipment able to inspect the filled bottles would have certainly an immediate applicability and a high potential of sales not only in Portugal, but also abroad.

Cooperation: UNICER - Bebidas de Portugal, S.A.

INSPECT - Inspection of Filled Bottles

video about bottle inspection

Development of a transducer displacement for monitoring applications in civil engineering

transducer displacement for monitoring applications in civil engineering

Leader: Fernando Gomes de Almeida
UISPA Team: Joaquim Gabriel Mendes, Maria Teresa Restivo
Period: From 2005 to 2006

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The project was funded by Universidade do Porto Rectory and Caixa Geral de Depósitos, Sept. 2004/August 2005. It has been a multidisciplinary project also including students and researchers from mechanical and civil engineering departments of Faculty of Engineering of University of Porto.

This project was a follow-up of a previous one, “Development of Displacement Transducers for Civil Engineering Applications”, and was focused on the characterization of the developed transducer sensitivity to external magnetic fields and environment temperature. If the first proved to be negligible the second one showed the need, on some extreme situations, for some kind of compensation. Consequently, some solutions were developed in order to decrease said temperature sensitivity to values compatible with the envisaged transducer application domain.

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Use of optical fibers for temperature and strain monitoring along and after curing process of a carbon fiber reinforced polymer

UISPA Team: Maria Teresa Restivo
Period: From 2005 to 2006

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The project was funded by Universidade do Porto Rectory and Caixa Geral de Depósitos, Sept. 2005/August2006. It has been a multidisciplinary project also including students and researchers from mechanical and civil engineering departments of Faculty of Engineering and physics department of Faculty of Sciences, both from University of Porto.

Optical Fiber sensors, if associated with composite materials, could be used in intelligent structures important for technological areas as aeronautics, civil engineering, robotics, etc.

A plate structure (smart structure) has been instrumented with a sensor head with two Bragg gratings. Studies were carried out and this solution has been implemented for the curing process in a carbon fiber reinforced polymer using hot press plates.

Development of a displacement transducer for civil engineering applications

displacement transducer for civil engineering applications

Leader: Maria Teresa Restivo
UISPA Team: Fernando Gomes de Almeida and Joaquim Gabriel Mendes
Period: From 2004 to 2005

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The project was funded by Universidade do Porto Rectory and and Fundação Ilídio Pinho, Sept. 2004/August 2005. It has been a multidisciplinary project also including students and researchers from mechanical and civil engineering departments of Faculty of Engineering of University of Porto.

A huge number of everyday applications need the measurement of displacement quantity in many points and they also require data acquisition and storage performed by stand alone systems of low power consumption for long periods of time. Examples are the monitoring of strains and part displacements in large structures such as buildings and bridges, the acquisition of seismic or weather, etc.

The project aims to develop a specific transducer for old historic buildings (of several centuries) requiring a non-obtrusive solutions and visually acceptable instrumentation. Such old buildings tend to develop cracks whose nature or reason is not completely understood, and must be followed for long periods of time to follow the evolution. Within this project a prototype of a displacement sensor, of low cost, with comparable characteristics to the market ones have been designed and produced. They have also been integrated in a CAN network system to acquire and store, for several months, data related to mechanical magnitudes in a large number of nodes. The transducers are based in Hall-effect sensors in a differential configuration.

This Project was award with a UPorto “Incentive to Research Prize, 2005” and a Patent PT 103546 was granted.

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Servopneumatic systems control

Servopneumatic systems control

Leader: Fernando Gomes de Almeida
UISPA Team: João Falcão Carneiro
Period: Since 2003

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The use of pneumatic devices is widespread among different industrial fields, in tasks like handling or assembly. Pneumatic systems are low-cost, reliable and compact solutions. However, its use is typically restricted to simple tasks due to the poor performance achieved in applications where accurate motion control is required.

In this project a contribution to the solution of this problem is being developed by making a thorough study on both modeling and control of servopneumatic systems. Previously obtained results show that a very accurate and robust controller to payload variations was already achieved: an accuracy of ±5 μm is achieved when arbitrarily positioning payloads ranging from 2.69 to 3.1kg. This performance is achieved without retuning the controller. Good results are also obtained in trajectory following tasks.

Cooperation: Fluidocontrol S. A.

Servopneumatic Systems Control

video about the servopneumatic

Neural network controllers for pneumatic actuators

Neural Network Controllers for Pneumatic Actuators

Leader: Fernando Gomes de Almeida
UISPA Team: Manuel Romano Barbosa and Manuel Rodrigues Quintas
Period: 1999

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In order to circumvent the control difficulties posed by pneumatic servosystems several nonlinear control techniques have been applied to these systems. Although a increase of performance may be observed the results provided by these controllers are still open for improvement. Artificial Neural Networks (ANNs) offer a novel approach to the control of nonlinear systems, leading to potentially higher achievable performance of pneumatic servosystems.

Several linear and non-linear controllers were developed. These at the same time as constituting a set of reference controllers also presented very good performances. The experimental evaluation of the developed controllers required the design and implementation of a laboratory prototype of the pneumatic servosystem. Another area of work was servo-valve modeling. Such development was required for controller design and simulation. In a first step, and leveraging on the research team experience, servo-hydraulic servo-valve models and simulation methodologies were developed, resulting into three journal papers and a significant fraction of a Ph.D. thesis. The same modeling methodology was afterwards applied to pneumatic servo-valves, this development being included in a M.Sc. thesis. This study required the design and implementation of an installation for air flow measurement on pneumatic servo-valves.

Relative Acceleration Transducer

Relative Acceleration Transducer

Leader: Maria Teresa Restivo
UISPA Team: Fernando Gomes de Almeida
Period: From 1998 to 2000

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The Project PUEM 04/95 was supported by Ministry of National Defence.

Inertial accelerometers provide measurements of absolute acceleration. Within the context of motion control systems, including machines, robots and other complex mechanical systems, indirect observation methods must be used when relative acceleration measurements are needed. These require the use of complex algorithms based on kinematic models that assume system rigidity. Such algorithms are very sensitive to parametric errors and to the accumulation of uncertainties from the measurements of absolute acceleration and of relative bodies’ positions, as well as of system dimensions. Another method for determining relative acceleration resorts to the differentiation of relative velocity signals (or double differentiation of displacement). But this solution requires signals of very high quality, with a very high signal to noise ratio.

This project aimed to develop a novel relative acceleration transducer that neither suffers from the limitations inherent to the use of absolute acceleration measurements nor applies the differentiation operator, as the methods referred above. Its working principle is based on the induction of eddy currents in a conductor, when it moves under a static magnetic field, to generate a pick-up signal in a sensing coil when relative velocity changes. This working principle leads naturally to a contactless type transducer, with linear detection of relative acceleration, easily adaptable to linear or angular motion.

The precision mechanics and the sensing element were designed. The transducer prototype was based on FEM studies. The experimental prototype has been patented (PT102697, BPI nº 2/2005, February 28, 2005).

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video about the acceleration transducer


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