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Prof. Fernando Gomes de Almeida
University of Porto - Faculty of Engineering

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Research Keywords & Expertise

0 Pneumatics
0 Robot Control
0 Mechanical design
0 Nonlinear Control
0 Fluid Power Control

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Mechanical design
Pneumatics
Nonlinear Control

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Short Biography

Fernando Gomes de Almeida is an Associate Professor of the Faculty of Engineering of the University of Porto. He got his Mechanical Engineering degree from the Faculty of Engineering of the University of Porto in 1984. He got his PhD degree in the field of model reference adaptive control of multi-axis hydraulic manipulators from Bath University, United Kingdom, in 1993. After that he has been conducting several courses, scientific activities and industrial consultancy work at the Faculty of Engineering of the University of Porto, first as Assistant Professor, and since 2011 in its present position. From 1997 to 2004 he assumed the direction of the Systems Integration and Automated Processes Unit of IDMEC nowadays integrated into the Associated Laboratory for Energy, Transports and Aeronautics. He participated as expert consultant in more than 35 projects (mostly industrial related), 7 of which as the leading project coordinator and 4 as leading scientific coordinator. The projects have covered several technical fields: e.g., pneumatic or hydraulic actuators control, robotic manipulation, data acquisition and monitoring, remote accurate measurement of displacements, remote laboratories, PET scan medical imaging machines for breast cancer detection, machine tool design.

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Journal article
Published: 15 July 2021 in Actuators
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In this paper, endurance of peristaltic linear pneumatic actuators was studied using different hose geometries. Towards this goal, different hose geometries were additively manufactured using Fused Layer Manufacturing techniques of Thermoplastic Polyurethane Elastomer. Material properties of the elastomer were studied using Differential Scanning Calorimetry and the tensile test. The relations between the sample’s print temperature and build direction on the actuator endurance were investigated. Lastly, the relation between the geometry design of the PLPA actuator and its endurance is also discussed. Based on this methodology, authors present results showing that the use of a customized shaped hose with geometrical reinforcement at sides leads to a considerable rise in the hose endurance, when compared with the conventional circular design.

ACS Style

Miranda Fateri; João Carneiro; Achim Frick; João Pinto; Fernando Gomes de Almeida. Additive Manufacturing of Flexible Material for Pneumatic Actuators Application. Actuators 2021, 10, 161 .

AMA Style

Miranda Fateri, João Carneiro, Achim Frick, João Pinto, Fernando Gomes de Almeida. Additive Manufacturing of Flexible Material for Pneumatic Actuators Application. Actuators. 2021; 10 (7):161.

Chicago/Turabian Style

Miranda Fateri; João Carneiro; Achim Frick; João Pinto; Fernando Gomes de Almeida. 2021. "Additive Manufacturing of Flexible Material for Pneumatic Actuators Application." Actuators 10, no. 7: 161.

Journal article
Published: 25 August 2020 in Actuators
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Pneumatic linear peristaltic actuators can offer some potential advantages when compared with conventional ones. Low cost, virtually unlimited stroke and easy implementation of curved motion profiles are among those benefits. On the downside, these actuators suffer high mechanical stress, which leads to short endurance and increased leakage between chambers during the actuator lifetime. This paper contributes to this field by experimentally characterizing the life behavior of a prototype of a linear pneumatic peristaltic actuator where force—instead of displacement—between rollers is imposed. It is shown that the use of an imposed force configuration has a significant impact in the actuator life time. In fact, the proposed actuator configuration has an average endurance of up to 250% higher than the one previously presented in the literature. This result was obtained while maintaining almost zero leakage between chambers, despite the hose wear throughout the service life. Finally, this paper explores the use of different hose geometries to increase the actuator life span. To this end, a preliminary study is presented where two different 3D printed hose cross sections are tested and compared with a circular one.

ACS Style

João Falcão Carneiro; João Bravo Pinto; Fernando Gomes De Almeida; Miranda Fateri. Improving Endurance of Pneumatic Linear Peristaltic Actuators. Actuators 2020, 9, 76 .

AMA Style

João Falcão Carneiro, João Bravo Pinto, Fernando Gomes De Almeida, Miranda Fateri. Improving Endurance of Pneumatic Linear Peristaltic Actuators. Actuators. 2020; 9 (3):76.

Chicago/Turabian Style

João Falcão Carneiro; João Bravo Pinto; Fernando Gomes De Almeida; Miranda Fateri. 2020. "Improving Endurance of Pneumatic Linear Peristaltic Actuators." Actuators 9, no. 3: 76.

Journal article
Published: 30 July 2020 in Actuators
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Pneumatic linear peristaltic actuators can offer some potential advantages when compared with conventional ones. The low cost, virtually unlimited stroke and easy implementation of curved motion profiles are among those benefits. On the downside, these actuators suffer high mechanical stress that can lead to short service life and increased leakage among chambers during the actuator lifetime. One way to cope with this problem is to impose the force—instead of the displacement—between rollers, as this has been shown to improve the endurance of the hose while reducing leakage during the actuator lifetime. This paper presents closed control loop results using such a setup. Previous studies with linear peristaltic actuators have revealed that, although it is possible to reach zero steady state error to constant references with closed loop control, the dynamic response obtained is very slow. This paper is mainly focused on this topic, namely on the development of several control laws to improve the dynamic performance of the system while avoiding limit cycles. The new developed control law leads to an average time of 1.67 s to reach a 0.1 mm error band in an experiment consisting of a series of 16 steps ranging from 0.02 to 0.32 m in amplitude.

ACS Style

João Falcão Carneiro; João Bravo Pinto; Fernando Gomes De Almeida. Accurate Motion Control of a Pneumatic Linear Peristaltic Actuator. Actuators 2020, 9, 63 .

AMA Style

João Falcão Carneiro, João Bravo Pinto, Fernando Gomes De Almeida. Accurate Motion Control of a Pneumatic Linear Peristaltic Actuator. Actuators. 2020; 9 (3):63.

Chicago/Turabian Style

João Falcão Carneiro; João Bravo Pinto; Fernando Gomes De Almeida. 2020. "Accurate Motion Control of a Pneumatic Linear Peristaltic Actuator." Actuators 9, no. 3: 63.

Journal article
Published: 14 July 2020 in IEEE Journal of Oceanic Engineering
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The growth of undersea exploration is pushing both the length and the complexity of propeller-driven autonomous underwater vehicles (AUVs) missions, leading to more stringent energy requirements. One approach to decrease the energy consumption of a hovering capable AUV is to use variable buoyancy systems (VBS) as a complement to the propeller actuators. These devices only require energy consumption during limited periods of time, taking into advantage the fact that whenever buoyancy is different from zero, the vehicle will continuously ascend or descend. Nevertheless, literature is scarce regarding the choice of the type of the VBS and of its constitutive elements, and regarding their effects on the energy required for buoyancy changes. This work presents structured and detailed static models of electromechanical and electrohydraulic VBSs that allow the calculation of the power required to actuate them. Based on the VBS desired characteristics and on manufacturer's data, the power consumption in each element of the VBS can be pinpointed to determine critical elements. Furthermore, a direct energy comparison with propeller-based solutions can be performed, allowing an easy evaluation of the energy gains provided by the VBS in different scenarios. This work also presents the preliminary development of an electromechanical and electrohydraulic VBS for an existing AUV at the University of Porto, Porto, Portugal. Based on the developed VBS and the developed model, numerical examples are provided for typical mission profiles. It is shown that the use of a VBS in the case of the existing AUV at the University of Porto leads to considerable energetic improvements.

ACS Style

Joao Falcao Carneiro; Joao Bravo Pinto; Fernando Gomes de Almeida; Nuno A. Cruz. Variable Buoyancy or Propeller-Based Systems for Hovering Capable Vehicles: An Energetic Comparison. IEEE Journal of Oceanic Engineering 2020, 46, 414 -433.

AMA Style

Joao Falcao Carneiro, Joao Bravo Pinto, Fernando Gomes de Almeida, Nuno A. Cruz. Variable Buoyancy or Propeller-Based Systems for Hovering Capable Vehicles: An Energetic Comparison. IEEE Journal of Oceanic Engineering. 2020; 46 (2):414-433.

Chicago/Turabian Style

Joao Falcao Carneiro; Joao Bravo Pinto; Fernando Gomes de Almeida; Nuno A. Cruz. 2020. "Variable Buoyancy or Propeller-Based Systems for Hovering Capable Vehicles: An Energetic Comparison." IEEE Journal of Oceanic Engineering 46, no. 2: 414-433.

Journal article
Published: 30 January 2020 in Information
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Pneumatic linear peristaltic actuators present several potential advantages over conventional ones such as low cost, virtually unlimited stroke, and an easy implementation of curved motion profiles. However, the body of this type of actuators also suffers from high mechanical stress, leading to a decrease in the hose wall thickness, which leads to increased leakages between chambers. One way to potentially minimize this problem is to impose the force instead of the displacement between rollers. This paper describes the model and experimental characteristics of a new prototype of a linear pneumatic peristaltic actuator where either the force or the displacement between rollers can be imposed. Namely, experimental friction characteristics and the leakage between chambers are determined in the configuration where the force between rollers is imposed. Lastly, a third-order linear model is experimentally identified. Therefore, this study establishes the basis for future research focused on the service life and leakage obtained whenever the force between rollers is imposed.

ACS Style

João Falcão Carneiro; João Bravo Pinto; Fernando Gomes De Almeida; Miranda Fateri. Model and Experimental Characteristics of a Pneumatic Linear Peristaltic Actuator. Information 2020, 11, 76 .

AMA Style

João Falcão Carneiro, João Bravo Pinto, Fernando Gomes De Almeida, Miranda Fateri. Model and Experimental Characteristics of a Pneumatic Linear Peristaltic Actuator. Information. 2020; 11 (2):76.

Chicago/Turabian Style

João Falcão Carneiro; João Bravo Pinto; Fernando Gomes De Almeida; Miranda Fateri. 2020. "Model and Experimental Characteristics of a Pneumatic Linear Peristaltic Actuator." Information 11, no. 2: 76.

Journal article
Published: 17 December 2019 in Information
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The growing needs in exploring ocean resources have been pushing the length and complexity of autonomous underwater vehicle (AUV) missions, leading to more stringent energy requirements. A promising approach to reduce the energy consumption of AUVs is to use variable buoyancy systems (VBSs) as a replacement or complement to thruster action, since VBSs only require energy consumption during limited periods of time to control the vehicle’s floatation. This paper presents the development of an electrohydraulic VBS to be included in an existing AUV for shallow depths of up to 100 m. The device’s preliminary mechanical design is presented, and a mathematical model of the device’s power consumption is developed, based on data provided by the manufacturer. Taking a standard mission profile as an example, a comparison between the energy consumed using thrusters and the designed VBS is presented and compared.

ACS Style

João Falcão Carneiro; João Bravo Pinto; Nuno A. Cruz; Fernando Gomes De Almeida. Development of an Electrohydraulic Variable Buoyancy System. Information 2019, 10, 396 .

AMA Style

João Falcão Carneiro, João Bravo Pinto, Nuno A. Cruz, Fernando Gomes De Almeida. Development of an Electrohydraulic Variable Buoyancy System. Information. 2019; 10 (12):396.

Chicago/Turabian Style

João Falcão Carneiro; João Bravo Pinto; Nuno A. Cruz; Fernando Gomes De Almeida. 2019. "Development of an Electrohydraulic Variable Buoyancy System." Information 10, no. 12: 396.

Conference paper
Published: 01 June 2019 in 2019 5th Experiment International Conference (exp.at'19)
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The energy requirements of thruster driven autonomous underwater vehicle (AUV) missions have been growing in recent years. Their complexity and length are continuously increasing due to the growth of undersea exploration. The use of variable buoyancy systems (VBS) can potentially lead to energy savings since consumption is only required for buoyancy changes. As such, energy is only spent during limited periods of time, as opposed to thruster driven systems, where consumption is typically continuous. In this work, an energetic comparison between thruster and VBS driven devices is performed for a specific mission profile and a defined set of parameters. The influence of the mission parameters is studied in order to determine which system leads to the lowest energy consumption. For the case study presented, it is shown that the use of VBS over thrusters can lead to considerable energetic savings.

ACS Style

Joao Falcao Carneiro; Joao Bravo Pinto; Fernando Gomes De Almeida; Nuno Cruz. Using a variable buoyancy system for energy savings in an AUV. 2019 5th Experiment International Conference (exp.at'19) 2019, 305 -309.

AMA Style

Joao Falcao Carneiro, Joao Bravo Pinto, Fernando Gomes De Almeida, Nuno Cruz. Using a variable buoyancy system for energy savings in an AUV. 2019 5th Experiment International Conference (exp.at'19). 2019; ():305-309.

Chicago/Turabian Style

Joao Falcao Carneiro; Joao Bravo Pinto; Fernando Gomes De Almeida; Nuno Cruz. 2019. "Using a variable buoyancy system for energy savings in an AUV." 2019 5th Experiment International Conference (exp.at'19) , no. : 305-309.

Original article
Published: 13 October 2018 in The International Journal of Advanced Manufacturing Technology
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Pneumatic actuators are typically discarded for applications where fine motion control is required, mainly due to the nonlinearities caused by friction effects between piston and rod seals. Conventional control laws are unable to counteract this phenomenon, and thus, conventional actuators find limited applicability in servo control systems. Recently, the use of an alternative solution, a pneumatic linear peristaltic actuator (PLPA), was proposed to overcome this problem. In its present embodiment, a PLPA comprehends two rollers pressing a hose and thereby defining two separate chambers. The use of a PLPA has several potential advantages over conventional or low friction actuators, but its endurance is yet to be known as no studies on this topic can be found in literature. This paper tries to fill this gap by presenting an experimental characterization of some mechanical properties of three different hoses, which are subsequently used in experimental endurance tests. This paper also presents a detailed description of the failure causes found and an analysis on how different parameters may influence its longevity. Finally, possible solutions to increase the life of PLPAs are envisaged.

ACS Style

João Falcão Carneiro; Fernando Almeida; João Pedro Pinto. Endurance tests of a linear peristaltic actuator. The International Journal of Advanced Manufacturing Technology 2018, 100, 2103 -2114.

AMA Style

João Falcão Carneiro, Fernando Almeida, João Pedro Pinto. Endurance tests of a linear peristaltic actuator. The International Journal of Advanced Manufacturing Technology. 2018; 100 (5-8):2103-2114.

Chicago/Turabian Style

João Falcão Carneiro; Fernando Almeida; João Pedro Pinto. 2018. "Endurance tests of a linear peristaltic actuator." The International Journal of Advanced Manufacturing Technology 100, no. 5-8: 2103-2114.

Original article
Published: 05 June 2018 in The International Journal of Advanced Manufacturing Technology
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Pneumatic actuators find widespread use in industry when motion between two end-points is required, given their high power to weight ratio and low maintenance requirements. However, classical PID control of pneumatic actuators may present several undesired features, such as large steady-state errors. In this work, a two servo-valve architecture was developed for the position control of a servo-pneumatic system. With this architecture, the two servo-valves are independently controlled—the one connected to the charging chamber is controlled so as to maintain an approximately constant pressure in the discharging chamber, while the other handles motion control. The use of this control architecture is justified through analysis of the system model. By using this architecture with linear PID-family controllers, the aim is to enhance motion smoothness and improve the steady-state errors usually obtained with PID controllers in classical architectures, where the control actions are applied symmetrically to each servo-valve. Both simulation and experimental results show that the newly developed architecture compares very favorably to the classical one in terms of motion smoothness, steady-state positioning errors, and robustness to load variations.

ACS Style

Paul Dólleman; João Falcão Carneiro; Fernando Gomes De Almeida. Exploring the use of two servo-valves for servo-pneumatic control. The International Journal of Advanced Manufacturing Technology 2018, 97, 3963 -3980.

AMA Style

Paul Dólleman, João Falcão Carneiro, Fernando Gomes De Almeida. Exploring the use of two servo-valves for servo-pneumatic control. The International Journal of Advanced Manufacturing Technology. 2018; 97 (9-12):3963-3980.

Chicago/Turabian Style

Paul Dólleman; João Falcão Carneiro; Fernando Gomes De Almeida. 2018. "Exploring the use of two servo-valves for servo-pneumatic control." The International Journal of Advanced Manufacturing Technology 97, no. 9-12: 3963-3980.

Journal article
Published: 01 May 2018 in Energy Conversion and Management
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ACS Style

João Falcão Carneiro; Fernando Almeida. Model and simulation of the energy retrieved by thermoelectric generators in an underwater glider. Energy Conversion and Management 2018, 163, 38 -49.

AMA Style

João Falcão Carneiro, Fernando Almeida. Model and simulation of the energy retrieved by thermoelectric generators in an underwater glider. Energy Conversion and Management. 2018; 163 ():38-49.

Chicago/Turabian Style

João Falcão Carneiro; Fernando Almeida. 2018. "Model and simulation of the energy retrieved by thermoelectric generators in an underwater glider." Energy Conversion and Management 163, no. : 38-49.

Original article
Published: 19 February 2018 in The International Journal of Advanced Manufacturing Technology
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Despite presenting several inherent advantages, pneumatic actuators are typically discarded for applications where fine motion control is required. This is mainly caused by friction effects caused by piston and rod seals, namely the discontinuities found in friction forces around zero velocity. These effects are very hard to predict and thus to counteract using conventional control laws. This paper explores the use of a different pneumatic actuation solution, a pneumatic linear peristaltic actuator (PLPA), to overcome this problem. The solution envisaged has several potential advantages over conventional or low-friction actuators. Since literature is scarce on this topic, this paper presents the working principle and the model of a PLPA, along with experimental results of its static and viscous friction forces. These results are compared against the ones obtained with a conventional low-friction actuator. Finally, the paper explores the use of a PLPA and a low-friction actuator for servo control, using a conventional PID-type controller. It is experimentally shown that, contrary to what happens with conventional (even low friction) actuators, the use of an integral action does not lead to a limit cycle. Moreover, zero steady-state control error is obtained in a closed loop step response, showing that the approach proposed in this study potentially leads to a low-cost and simple motion control solution.

ACS Style

João Falcão Carneiro; Fernando Almeida. Friction characteristics and servo control of a linear peristaltic actuator. The International Journal of Advanced Manufacturing Technology 2018, 96, 2117 -2126.

AMA Style

João Falcão Carneiro, Fernando Almeida. Friction characteristics and servo control of a linear peristaltic actuator. The International Journal of Advanced Manufacturing Technology. 2018; 96 (5-8):2117-2126.

Chicago/Turabian Style

João Falcão Carneiro; Fernando Almeida. 2018. "Friction characteristics and servo control of a linear peristaltic actuator." The International Journal of Advanced Manufacturing Technology 96, no. 5-8: 2117-2126.

Journal article
Published: 01 October 2016 in Energy
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ACS Style

J. Falcão Carneiro; F. Gomes de Almeida. Model of a thermal driven volumetric pump for energy harvesting in an underwater glider. Energy 2016, 112, 28 -42.

AMA Style

J. Falcão Carneiro, F. Gomes de Almeida. Model of a thermal driven volumetric pump for energy harvesting in an underwater glider. Energy. 2016; 112 ():28-42.

Chicago/Turabian Style

J. Falcão Carneiro; F. Gomes de Almeida. 2016. "Model of a thermal driven volumetric pump for energy harvesting in an underwater glider." Energy 112, no. : 28-42.

Journal article
Published: 28 September 2016 in IEEE Access
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Pneumatic systems are clean and reliable actuators, presenting very high force to weight ratios. They further present some advantages like inherent compliance and suitability for fire hazard environments. However, their intrinsic nonlinearities have hindered a more wide range of applications, leading to the use of complex control laws that typically require the knowledge of velocity and acceleration. This means that velocity and acceleration estimators might play a crucial role in servopneumatic systems control, since a difficult to achieve balance between differentiation noise and phase lag must be inferred by the control engineer. This work experimentally compares the performance of several velocity and acceleration estimators, relying upon a digital encoder position signal. The comparison is performed not only regarding the quality of the actual estimates per se but also on their effect on the control error and control action obtained when using a nonlinear sliding mode based controller.

ACS Style

João Falcão Carneiro; Fernando Gomes De Almeida. On the Influence of Velocity and Acceleration Estimators on a Servopneumatic System Behaviour. IEEE Access 2016, 4, 6541 -6553.

AMA Style

João Falcão Carneiro, Fernando Gomes De Almeida. On the Influence of Velocity and Acceleration Estimators on a Servopneumatic System Behaviour. IEEE Access. 2016; 4 (99):6541-6553.

Chicago/Turabian Style

João Falcão Carneiro; Fernando Gomes De Almeida. 2016. "On the Influence of Velocity and Acceleration Estimators on a Servopneumatic System Behaviour." IEEE Access 4, no. 99: 6541-6553.

Randomized controlled trial
Published: 13 July 2016 in Journal of Clinical Monitoring and Computing
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The assessment of the adequacy of general anesthesia for surgery, namely the nociception/anti-nociception balance, has received wide attention from the scientific community. Monitoring systems based on the frontal EEG/EMG, or autonomic state reactions (e.g. heart rate and blood pressure) have been developed aiming to objectively assess this balance. In this study a new multivariate indicator of patients’ steady-state during anesthesia (STAN) is proposed, based on wavelet analysis of signals linked to noxious activation. A clinical protocol was designed to analyze precise noxious stimuli (laryngoscopy/intubation, tetanic, and incision), under three different analgesic doses; patients were randomized to receive either remifentanil 2.0, 3.0 or 4.0 ng/ml. ECG, PPG, BP, BIS, EMG and \(\hbox {CO}_{2}\) were continuously recorded. ECG, PPG and BP were processed to extract beat-to-beat information, and \(\hbox {CO}_{2}\) curve used to estimate the respiration rate. A combined steady-state index based on wavelet analysis of these variables, was applied and compared between the three study groups and stimuli (Wilcoxon signed ranks, Kruskal–Wallis and Mann–Whitney tests). Following institutional approval and signing the informed consent thirty four patients were enrolled in this study (3 excluded due to signal loss during data collection). The BIS index of the EEG, frontal EMG, heart rate, BP, and PPG wave amplitude changed in response to different noxious stimuli. Laryngoscopy/intubation was the stimulus with the more pronounced response \((P<0.05)\). These variables were used in the construction of the combined index STAN; STAN responded adequately to noxious stimuli, with a more pronounced response to laryngoscopy/intubation (18.5–43.1 %, \(P<0.05\)), and the attenuation provided by the analgesic, detecting steady-state periods in the different physiological signals analyzed (approximately 50 % of the total study time). A new multivariate approach for the assessment of the patient steady-state during general anesthesia was developed. The proposed wavelet based multivariate index responds adequately to different noxious stimuli, and attenuation provided by the analgesic in a dose-dependent manner for each stimulus analyzed in this study.

ACS Style

Ana Castro; Fernando Almeida; Pedro Amorim; Catarina Nunes. A novel multivariate STeady-state index during general ANesthesia (STAN). Journal of Clinical Monitoring and Computing 2016, 31, 851 -860.

AMA Style

Ana Castro, Fernando Almeida, Pedro Amorim, Catarina Nunes. A novel multivariate STeady-state index during general ANesthesia (STAN). Journal of Clinical Monitoring and Computing. 2016; 31 (4):851-860.

Chicago/Turabian Style

Ana Castro; Fernando Almeida; Pedro Amorim; Catarina Nunes. 2016. "A novel multivariate STeady-state index during general ANesthesia (STAN)." Journal of Clinical Monitoring and Computing 31, no. 4: 851-860.

Conference paper
Published: 01 April 2016 in 2016 Eleventh International Conference on Ecological Vehicles and Renewable Energies (EVER)
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Underwater gliders enable an increase of human presence in the oceans. A particularly interesting solution lies in the use of the thermal gradient of the ocean as a means to provide energy to the vehicle. These type of gliders - thermal gliders - may remain years underwater collecting and transmitting data to seashore. A key element of these vehicles is the thermal driven volumetric pump that enables energy harvesting. In this paper a new quasi-static model of a thermal driven volumetric pump, for use in underwater gliders, is presented. The system considered includes a Phase Change Material (PCM) to convert thermal to mechanical energy and a hydraulic accumulator to store retrieved energy. The model allows the description of the quasi-static behaviour of the PCM coupled to the hydraulic system. The full thermodynamic cycle of the system can thus be simulated so that, in future works, the parameters of the system can be tuned for optimal performance.

ACS Style

Joao Falcao Carneiro; Fernando Gomes De Almeida. Quasi-static model of a thermal driven volumetric pump for an underwater glider. 2016 Eleventh International Conference on Ecological Vehicles and Renewable Energies (EVER) 2016, 1 -8.

AMA Style

Joao Falcao Carneiro, Fernando Gomes De Almeida. Quasi-static model of a thermal driven volumetric pump for an underwater glider. 2016 Eleventh International Conference on Ecological Vehicles and Renewable Energies (EVER). 2016; ():1-8.

Chicago/Turabian Style

Joao Falcao Carneiro; Fernando Gomes De Almeida. 2016. "Quasi-static model of a thermal driven volumetric pump for an underwater glider." 2016 Eleventh International Conference on Ecological Vehicles and Renewable Energies (EVER) , no. : 1-8.

Journal article
Published: 01 January 2016 in IFAC-PapersOnLine
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This work presents a remote monitoring and control solution for a level measurement system. The level measurement system comprises two tanks in a closed loop water circuit, some level transducers, detectors and two actuators. The developed solution is based on microcontrollers and web services. The web interface allows the user to remotely interact with the level measurement and control system.

ACS Style

Maria De Fátima Chouzal; Maria Teresa Restivo; Fernando Gomes Silva; Fernando Gomes Almeida; Tiago Faustino Andrade. Remote Level Monitoring and Control Solution. IFAC-PapersOnLine 2016, 49, 194 -197.

AMA Style

Maria De Fátima Chouzal, Maria Teresa Restivo, Fernando Gomes Silva, Fernando Gomes Almeida, Tiago Faustino Andrade. Remote Level Monitoring and Control Solution. IFAC-PapersOnLine. 2016; 49 (6):194-197.

Chicago/Turabian Style

Maria De Fátima Chouzal; Maria Teresa Restivo; Fernando Gomes Silva; Fernando Gomes Almeida; Tiago Faustino Andrade. 2016. "Remote Level Monitoring and Control Solution." IFAC-PapersOnLine 49, no. 6: 194-197.

Conference paper
Published: 01 January 2015 in Lecture Notes in Electrical Engineering
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Pneumatic systems offer a wide range of load capacity and velocities, present advantageous power to weight ratios and do not generate thermal or magnetic fields. However, their broader use in industry has been hindered by the difficulties found in fine motion or force control. Amongst the several phenomena that contribute to this scenario, friction in piston and rod seals is probably the most important one. Industrial pneumatic cylinders present friction forces with several undesired features for control purposes like highly nonlinear behavior, hysteresis and dwell time dependence. The LuGre friction model presents a good trade-off between complexity and accuracy. In this work the LuGre model of an industrial pneumatic cylinder is identified and validated using experimental data. Static and dynamic parameters are estimated using a procedure described in literature and a new procedure to estimate one of the dynamic parameters is proposed. A comparison between both methods is provided.

ACS Style

João Falcão Carneiro; Fernando Gomes de Almeida. LuGre Friction Model: Application to a Pneumatic Actuated System. Lecture Notes in Electrical Engineering 2015, 459 -468.

AMA Style

João Falcão Carneiro, Fernando Gomes de Almeida. LuGre Friction Model: Application to a Pneumatic Actuated System. Lecture Notes in Electrical Engineering. 2015; ():459-468.

Chicago/Turabian Style

João Falcão Carneiro; Fernando Gomes de Almeida. 2015. "LuGre Friction Model: Application to a Pneumatic Actuated System." Lecture Notes in Electrical Engineering , no. : 459-468.

Journal article
Published: 13 November 2014 in The International Journal of Advanced Manufacturing Technology
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Pneumatic systems are a simple and readily available technology that presents high force to volume ratios. Their use is nevertheless restricted to simple motion tasks, given the complexity in its modelling and control. One of the main aspects contributing to this panorama is the difficulty in accurately predicting friction forces. In fact, although it is possible to find in literature complex friction models that suit well a particular experimental set-up, its practical use becomes hindered given the diversity of pneumatic actuated systems found in industry. This paper presents a new controller that achieves very good results even without a friction model. The controller architecture includes a robust motion control loop and a non-linear state feedback pneumatic force loop. The motion controller law is based on integral sliding control and takes into account the pneumatic dynamics, using it as a natural filter of the discontinuous part of the control law. Experimental results show that the proposed approach leads to low tracking and positioning errors. These results are obtained without including a friction model and even in the presence of parameter disturbances caused by a fivefold payload change, without any controller retuning or excessive control action activity.

ACS Style

João Falcão Carneiro; F. Gomes De Almeida. Accurate motion control of a servopneumatic system using integral sliding mode control. The International Journal of Advanced Manufacturing Technology 2014, 77, 1533 -1548.

AMA Style

João Falcão Carneiro, F. Gomes De Almeida. Accurate motion control of a servopneumatic system using integral sliding mode control. The International Journal of Advanced Manufacturing Technology. 2014; 77 (9):1533-1548.

Chicago/Turabian Style

João Falcão Carneiro; F. Gomes De Almeida. 2014. "Accurate motion control of a servopneumatic system using integral sliding mode control." The International Journal of Advanced Manufacturing Technology 77, no. 9: 1533-1548.

Clinical trial
Published: 30 October 2014 in Journal of Clinical Monitoring and Computing
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Somatosensory evoked potentials (SEPs) have been linked to noxious activation and stimulus intensity. In this exploratory study we investigated the impact of anaesthetic drugs on SEPs and pain ratings, to assess their applicability as an objective measure of the nociception/anti-nociception balance. Following institutional approval and written informed consent, 10 healthy adult volunteers were enrolled (29.5 ± 9.1 years, 63.0 ± 8.9 kg and 171.4 ± 7.2). Median nerve electrical stimulation was adjusted according to volunteers’ sensitive, motor and painful thresholds (PT). Baseline SEPs were registered, and remifentanil and propofol administered using a stair scheme TCI. For each drug combination a 1.3×PT stimulus was administered, and volunteers evaluated pain intensity in a numerical rating scale (0–10). SEPs’ amplitudes and latencies were normalized by the baseline values, reducing volunteers’ intervariability. Stimulation currents varied between 6–52 mA (1.3×PT) and pain ratings between 0 and 9. Cortical SEPs latencies were decreased for higher stimulus intensities (P P SEPs amplitude and interpeak latency is proposed( \(R_{Norm}\) ): \(R_{Norm}\) and NSR were significantly correlated in three out of nine subjects, and \(R_{Norm}\) and remifentanil Ce were significantly correlated in two (low number of evaluation points). \(R_{Norm}\) was shown to decrease with increasing doses of propofol and remifentanil (P

ACS Style

Ana Castro; Pedro Amorim; Catarina S. Nunes; Fernando Gomes De Almeida. Effect of propofol and remifentanil on a somatosensory evoked potential indicator of pain perception intensity in volunteers. Journal of Clinical Monitoring and Computing 2014, 29, 561 -567.

AMA Style

Ana Castro, Pedro Amorim, Catarina S. Nunes, Fernando Gomes De Almeida. Effect of propofol and remifentanil on a somatosensory evoked potential indicator of pain perception intensity in volunteers. Journal of Clinical Monitoring and Computing. 2014; 29 (5):561-567.

Chicago/Turabian Style

Ana Castro; Pedro Amorim; Catarina S. Nunes; Fernando Gomes De Almeida. 2014. "Effect of propofol and remifentanil on a somatosensory evoked potential indicator of pain perception intensity in volunteers." Journal of Clinical Monitoring and Computing 29, no. 5: 561-567.

Journal article
Published: 01 October 2014 in International Journal of Refrigeration
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Paulo R. Pereira; Szabolcs Varga; João Soares; Armando C. Oliveira; António M. Lopes; Fernando G. de Almeida; João F. Carneiro. Experimental results with a variable geometry ejector using R600a as working fluid. International Journal of Refrigeration 2014, 46, 77 -85.

AMA Style

Paulo R. Pereira, Szabolcs Varga, João Soares, Armando C. Oliveira, António M. Lopes, Fernando G. de Almeida, João F. Carneiro. Experimental results with a variable geometry ejector using R600a as working fluid. International Journal of Refrigeration. 2014; 46 ():77-85.

Chicago/Turabian Style

Paulo R. Pereira; Szabolcs Varga; João Soares; Armando C. Oliveira; António M. Lopes; Fernando G. de Almeida; João F. Carneiro. 2014. "Experimental results with a variable geometry ejector using R600a as working fluid." International Journal of Refrigeration 46, no. : 77-85.