Aníbal T. de Almeida

Aníbal T. de Almeida
University of Coimbra | UC · Institute of Systems & Robotics

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465
Publications
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Publications

Publications (465)
Conference Paper
Full-text available
Voltage-source inverters (VSIs) are widely used to control the speed and torque of three-phase squirrel cage induction motors (IMs), which represent the most important electrical load in industry. Nowadays , different VSI-technologies are commercially available, having different impacts on the performance and reliability of IMs. When compared to th...
Conference Paper
Full-text available
The use-phase cost of most electric industrial motors, namely the consumed energy, dominates by far their overall life-cycle cost. As a consequence of the EuP directive 2005/32/EC of the European Parliament and of the Council, a study to identify and recommend ways to improve the life-cycle environmental performance of electric motors at their desi...
Conference Paper
Full-text available
The line-start permanent-magnet synchronous motor (LSPMSM), with starting squirrel cage, is a promising technology to reach the Super-Premium/IE4 efficiency level indicated in the new IEC 60034-30 Standard, maintaining the IEC standard motor frame size in each power level and the line-start capability. In fact, many experts see LSPMSM as the most p...
Conference Paper
Full-text available
Most three-phase, squirrel-cage, induction motors (IMs) are oversized. In the European Union (EU), the average load factor of IMs is slightly lower than 60%. In fact, in some industrial sectors, a large quantity of motors operates with a load permanently significantly under that value (e.g., 25-30%). Therefore, since the load factor is an average o...
Conference Paper
Full-text available
Most three-phase, squirrel-cage, induction motors (IMs) are oversized. In the European Union, the average load factor of IMs is slightly lower than 60%. In fact, in some industrial sectors, a large quantity of motors operates with a load permanently under that value (e.g., 25-30%). If the motor load is properly estimated, as well as the voltage lev...
Article
Full-text available
E‐waste is rapidly turning into another man‐made disaster. We propose that a paradigm shift toward a more sustainable future can be made through soft‐matter electronics that are resilient, repairable if damaged, and recyclable (3R), provided that they achieve the same level of maturity as industrial electronics. This includes high‐resolution patter...
Article
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Despite the rapid progress on soft and stretchable batteries, current fabrication techniques involve manual disposition and stencil/screen printing. Here, for the first time, a 3D‐printed Ag–Ga battery is introduced through subsequent printing of four sinter‐free composites: a stretchable Liquid Metal (LM) EGaIn‐Ag‐Styrene‐isoprene block copolymers...
Article
Semitransparent and Conductive Electrodes In article number 2101238, Mahmoud Tavakoli and colleagues demonstrate that graphene oxide‐coated liquid metal nanoparticles can be transformed to semitransparent and conductive electrodes, through a rapid, low‐cost, and scalable laser processing technique. The authors used an infrared laser source for simu...
Conference Paper
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This article introduces a tailor-made smart glove that integrates resistive strain and pressure sensors. A homemade silver-based stretchable ink is screen printed over textile to create a strain sensor that estimates finger bending for all fingers. Another piezoresistive ink was synthesized, and screen printed on fingertips, using a specific archit...
Article
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Achieving nearly zero-energy buildings (nZEB) is one of the main objectives defined by the European Union for achieving carbon neutrality in buildings. nZEBs are heavily reliant on distributed renewable generation energy sources, which create new challenges associated with their inherent intermittency. To achieve nZEB levels, demand management play...
Article
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The global COVID-19 pandemic causes hundreds of thousands of deaths and has created a catastrophic economic and health crisis around the World. Transportation, manufacturing industries, business and people’s movement came to almost a halt and sharp oil and gas prices reduction were observed. The impact of the pandemic for sub-Saharan countries like...
Article
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Nowadays, modeling tools are a crucial part of best practice in the elaboration and implementation of a decarbonization plan in any organization, city, or country. The present review analyzes the different modeling tools available to assess energy systems in smart cities. It creates an updated overview of the modeling tools currently available, sho...
Article
Graphene encapsulated liquid metal particles is a novel and promising class of biphasic composite, with application in the next generation of electronic devices. Here, rapid, low-cost, and scalable fabrication of solution processed large area rGO@EGaIn electrodes is demonstrated. rGO@EGaIn solution is first deposited over the substrate through spra...
Article
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The use of low efficient cookstoves has several severe negative impacts. Burning solid fuels kills about 4 million people every year, a number which is higher than the combined impact of HIV-AIDS, malaria and tuberculosis. Moreover, most of the people affected are located in rural areas of Sub-Saharan Africa and other developing countries, where ov...
Article
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Integration of solid-state microchips into soft-matter, and stretchable printed electronics has been the biggest challenge against their scalable fabrication. We introduce, Pol-Gel, a simple technique for self-soldering, self-encapsulation, and self-healing, that allows low cost, scalable, and rapid fabrication of hybrid microchip-integrated ultra-...
Article
This paper investigates the sustainability of Tabriz City focusing on its decarbonization. Statistical, quantitative, and comparative research methods are used to analyze the total energy consumed, conversion of primary energy, final exergy, and losses analysis according to the renewable and carbon-based energies. Then, the renewable resource poten...
Article
A bi-phasic ternary Ag-In-Ga ink that demonstrates high electrical conductivity, extreme stretchability, and low electromechanical gauge factor (GF) is introduced. Unlike popular liquid metal alloys such as eutectic gallium-indium (EGaIn), this ink is easily printable and nonsmearing and bonds strongly to a variety of substrates. Using this ink and...
Article
Worldwide, about 3 billion people, mainly located in rural areas, do not have access to clean cooking, due to lack of electricity access, low availability and affordability of clean cooking technologies. Most clean cookstoves are claimed to be energy-efficient and cost-effective, but there is a lack of independent comparative analysis with differen...
Article
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Energy access is critical for health, education and social welfare improvements. In countries like Ethiopia, with a low electrification rate and with the majority of the population located in rural areas, about 76% of primary schools do not have access to electricity. This limits the hours of classes and does not allow the use of basic or modern te...
Article
This work addresses two well-known problems of tissue-interfacing hydrogels, that is, rapid drying and skin adhesion. These are considered as the main barriers against the wider application of hydrogels in many fields, including wearable bioelectronics. We demonstrate for the first time a hydrogel with a double solvent that is softer than the skin...
Article
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Today’s cities are estimated to generate 80% of global GDP, covering only about 3% of the land, but contributing to about 72% of all global greenhouse gas emissions. Cities face significant challenges, such as population growth, pollution, congestion, lack of physical and social infrastructures, while trying to simultaneously meet sustainable energ...
Article
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Recurring and increasing large-scale wildfires across the globe (e.g., Southern Europe, California, Australia), as a result of worsening climate conditions with record temperatures, drought, and strong winds, present a challenge to mankind. Early fire detection is crucial for a quick reaction and effective firefighting operations, minimizing the ri...
Article
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Electroencephalography (EEG) has a wide range of applications in medical diagnosis, and novel form of Human Machine Interfaces (HMI) for controlling prosthetic implants, wheelchairs, and home appliances in various forms of paralysis. However, the current EEG setups are composed of many wires hanging down from the system, and individual electrodes t...
Article
A novel technique that permits, for the first time, fabrication of stretchable traces with linewidths as low as 20 µm and line‐spacing of 30 µm, based on simple coating and printing techniques, performed entirely at ambient condition, is demonstrated. By relying on existing inkjet printing technique, the proposed sinter‐free method is a step toward...
Article
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Recognition of the energy savings potential in motor driven systems has led to the development of energy efficiency testing and classification standards for motors and end-use equipment (e.g., pumps and fans) and the implementation of minimum energy performance regulations targeting them worldwide. However, these standards and regulations have been...
Article
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This study proposes an induction motor drive system based on the LC filter integrated quasi‐Z source indirect matrix converter (QZS‐IMC). The proposed drive system shows the following features: (i) variable voltage control of inductor motor is achieved by the rectifier stage and variable frequency control is achieved by the inverter stage; (ii) aut...
Article
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Bioelectronics stickers that interface the human epidermis and collect electrophysiological data will constitute important tools in the future of healthcare. Rapid progress is enabled by novel fabrication methods for adhesive electronics patches that are soft, stretchable and conform to the human skin. Yet, the ultimate functionality of such system...
Article
In this paper, a study of a tubular linear actuator with a hybrid core is presented. Through a finite-element analysis software and force measurements it is shown that by using a hybrid core combining a permanent magnet and a ferromagnetic material, higher force density can be achieved compared to the utilization of a ferromagnetic core alone. Also...
Article
Stretchable electronics stickers that adhere to the human skin and collect biopotentials are becoming increasingly popular for biomonitoring applications. Such stickers should include electrodes, stretchable interconnects, silicon chips for processing and communication, and batteries. Here, we demonstrate a material architecture and fabrication tec...
Article
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The existing single‐phase, quasi‐Z‐source inverter (qZSI), photovoltaic (PV) power system with integrated battery energy storage (BES), abbreviated as BES‐qZSI‐PV power system, has several well‐known advantages, but cannot operate at night because there is no PV power input. In this study, a solution to overcome this issue is proposed. First, the p...
Article
The electric motor market has witnessed a major change in the last decade in several aspects: in structure, with company mergers contributing to a more global market, in content with energy-efficiency policies, and in its economy due to increasing electricity prices, all aspects contributing to push the market towards more energy-efficient electric...
Conference Paper
In this paper, several multiflux, three-phase induction motors, dual-winding configurations are experimentally analysed. Using a motor with two reconfigurable stator windings sharing the same slots, several dual-winding configurations with different spatial displacement between the two partial windings, are experimentally tested. A programmable vol...
Article
Surface Electromyography (sEMG) based Hand Gesture Recognition (HGR) is finding its application as a general-purpose wearable Human Machine Interface (HMI). However, the same is rarely explored for Foot Gesture Recognition (FGR). FGR is interesting as a hands-free controller, e.g. in case of an electric guitar player who controls the musical effect...
Article
We tackle two well-known problems in the fabrication of stretchable electronics: interfacing soft circuit wiring with silicon chips and fabrication of multi-layer circuits. We demonstrate techniques that allow integration of embedded flexible printed circuit boards (FPCBs) populated with microelectronics into soft circuits composed of liquid metal...
Article
We introduce a soft ultrathin and stretchable electronic skin with surface mounted components that can be transferred and wrapped around any 3D surface or self-adhere to human skin. The ~5 µm thick circuit is fabricated by printing the pattern over a temporary tattoo paper using a desktop laser printer, which is then coated with a silver ink and eu...
Conference Paper
Liquid metal (LM) alloys such as eutectic gallium indium (EGaIn) and gallium-indium-tin (Galinstan) have been used in the fabrication of soft and stretchable electronics during the past several years. The liquid-phase and high electrical conductivity of these materials make them one of the best candidates for fabrication of deformable electronics a...
Article
Integration of surface EMG sensors as an input source for Human Machine Interfaces (HMIs) is getting an increasing attention due to their application in wearable devices such as armbands. For a wearable device, comfort and lightness are important factors. Therefore, in this article we focus on a minimalistic approach, in which we try to classify fo...
Conference Paper
In this paper, a study of a small-diameter tubular linear motor for biomedical applications is presented. The performance of the motor, through its maximum force and losses, is evaluated as a function of the variation of several design parameters. This is done by performing a numerical analysis using a finite-element analysis software. Moreover, us...
Conference Paper
Full-text available
The global induction motor market is moving fast towards the higher efficiency classes, such as premium efficiency (IE3) and super-premium efficiency (IE4) classes. Despite that, the existing operating motor stock is still dominated by below-standard and standard motors, since, on average, induction motors, regardless their efficiency classes, can...
Conference Paper
According to the World Health Organization, nearly 3 billion people burn wood, crop wastes, charcoal, coal and animal dung to meet their day to day energy needs and among these nearly 1.3 billion people do not have electricity access. More than 80% of the population suffering from energy poverty are living in rural areas of developing countries, su...
Article
Coating inkjet‐printed traces of silver nanoparticle (AgNP) ink with a thin layer of eutectic gallium indium (EGaIn) increases the electrical conductivity by six‐orders of magnitude and significantly improves tolerance to tensile strain. This enhancement is achieved through a room‐temperature “sintering” process in which the liquid‐phase EGaIn allo...
Article
Purpose The purpose of this study was to design a renovation plan for a university campus building (Department of Electrical and Computer Engineering) with the aim to achieve nearly zero energy performance, ensuring a low specific demand (lower than 44 kWh/m ² ) and a high level of on-site renewable generation (equivalent to more than 20 per cent o...
Article
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Current industrial fabrication and automation systems are faced with the challenge of obtaining great accuracy and fine manipulation over a large workspace. In this article, SCALA, a novel framework for robots that move on modular ad-hoc dedicated rails is presented. The goal is to have several agents moving simultaneously and rapidly on these scaf...
Article
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Single-phasing is one of the major causes of motor failure in the industry. The electric motor market is changing fast due to the minimum energy performance standards being adopted around the World. In a large number of cases, particularly when the original old motors are retrofitted with motors of higher efficiency classes, the respective overload...
Article
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In the last decades, it has been recognized that energy consumption in low power modes for electrical and electronic products is an important issue. There is a need to expand energy efficiency efforts beyond simple standby modes into the new more complex area of networks, thus tackling the new paradigm of living based on the Internet of Things. The...
Article
One of the main problems affecting parallel robots in industry is the low workspace to installation-space ratio. In this paper, the novel concept of a 3-P⌃UR (three-prismatic-translation and rotation universal-rotation) reconfigurable spatial parallel manipulator, driven by 2D mobile robots, is presented. Using three strategies on the same system,...
Article
Some design methodologies for Parallel Kinematic Machines (PKM) have been proposed but with limitations regarding two main problems: how to improve multiple properties of different nature such as accuracy, force or singularity poses, and how to check these properties for all poses inside the PKM workspace. To address these problems, this work propo...
Article
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Electric-motor systems convert nearly half of worldwide electric energy into the mechanical energy ultimately used in the final application or process. The integral optimization of electric-motor-driven systems (EMODSs), including the use of high-efficiency, well-sized components, is the key strategy to effectively maximize their overall efficiency...
Article
In this paper, a prototype of the SCALA - SCAlable ModuLar Multi-Agent Robotic System is developed and implemented. This system for automation in large spaces, relies on mobile agents which move on a planar and modular mesh of rails, with embedded accurate positioning sensors. Groups of three mobile agents are joined together to drive a parallel ma...
Article
Soft matter capacitive sensors are developed and integrated into the silicone skin of finger tips and palm of a robotic hand. Distributed sensing nodes are used for obtaining preliminary pre-touch information about the object that should be grasped. This includes conductive objects taking advantage of proximity sensing from changes in electric fiel...
Article
Motors systems are a major electricity consumer (about 70% of the industrial electricity consumption and about 35% in the non-residential buildings sector). Several studies showed the very large energy saving potential deriving from motor improved efficiency. After a period of Voluntary Agreement with a somehow limited impact, the EU introduced in...
Conference Paper
In this article we present an innovative and bio-inspired design of fingers that resembles the physiology of a biological finger. This includes a 3D-printed core to substitute the fingers endoskeleton, a silicon elastomer skin to substitute the elastic and resilient epidermal layer and a hydrogel filling to substitute the dermal layer. The dermal l...
Conference Paper
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The development of upper limb prostheses had a great growth with the proliferation of additive manufacturing technologies. This article suggests the design and development of a novel Bio-inspired compliant finger which is composed of a 3D printed rigid endoskeleton covered by soft matter, to apply to body actuated upper limb prostheses. We demonstr...
Article
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Mandatory regulations worldwide are being adopted by several countries to accelerate the motor market transformation toward Premium/IE3 and Super Premium/IE4 efficiency classes. However, besides motor efficiency, there are other important operation issues in the scope of modern industrial plants which also have to be taken into account when decidin...
Article
Photovoltaic generation, due to its decreasing cost and versatility, has seen a growing utilization in residential buildings. However, the mismatch between the demand and the photovoltaic generation profiles leads to high power flows between the household and the grid. The appearance of tariffs that foster the self-consumption and penalize the inje...
Article
Climate and energy targets, as well as decreasing costs have been leading to a growing utilization of solar photovoltaic generation in residential buildings. However, even in buildings with the same level of yearly generation and consumption the mismatch between the demand and photovoltaic generation profiles leads to large power flows between the...