A Review of Smart Materials in Tactile Actuators for Information Delivery

As the largest organ in the human body, the skin provides the important sensory channel for humans to receive external stimulations based on touch. By the information perceived through touch, people can feel and guess the properties of objects, like weight, temperature, textures, and motion, etc. In fact, those properties are nerve stimuli to our brain received by different kinds of receptors in the skin. Mechanical, electrical, and thermal stimuli can stimulate these receptors and cause different information to be conveyed through the nerves. Technologies for actuators to provide mechanical, electrical or thermal stimuli have been developed. These include static or vibrational actuation, electrostatic stimulation, focused ultrasound, and more. Smart materials, such as piezoelectric materials, carbon nanotubes, and shape memory alloys, play important roles in providing actuation for tactile sensation. This paper aims to review the background biological knowledge of human tactile sensing, to give an understanding of how we sense and interact with the world through the sense of touch, as well as the conventional and state-of-the-art technologies of tactile actuators for tactile feedback delivery

A lightweight, high strength dexterous manipulator for commercial applications

The concept, design, and features are described of a lightweight, high strength, modular robot manipulator being developed for space and commercial applications. The manipulator has seven fully active degrees of freedom and is fully operational in 1 G. Each of the seven joints incorporates a unique drivetrain design which provides zero backlash operation, is insensitive to wear, and is single fault tolerant to motor or servo amplifier failure. Feedback sensors provide position, velocity, torque, and motor winding temperature information at each joint. This sensing system is also designed to be single fault tolerant. The manipulator consists of five modules (not including gripper). These modules join via simple quick-disconnect couplings and self-mating connectors which allow rapid assembly and/or disassembly for reconfiguration, transport, or servicing. The manipulator is a completely enclosed assembly, with no exposed components or wires. Although the initial prototype will not be space qualified, the design is well suited to meeting space requirements. The control system provides dexterous motion by controlling the endpoint location and arm pose simultaneously. Potential applications are discussed

Surface Plasmon Excitation of Second Harmonic light: Emission and Absorption

We aim to clarify the role that absorption plays in nonlinear optical processes in a variety of metallic nanostructures and show how it relates to emission and conversion efficiency. We define a figure of merit that establishes the structure's ability to either favor or impede second harmonic generation. Our findings suggest that, despite the best efforts embarked upon to enhance local fields and light coupling via plasmon excitation, nearly always the absorbed harmonic energy far surpasses the harmonic energy emitted in the far field. Qualitative and quantitative understanding of absorption processes is crucial in the evaluation of practical designs of plasmonic nanostructures for the purpose of frequency mixing

Automotive gestures recognition based on capacitive sensing

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e ComputadoresDriven by technological advancements, vehicles have steadily increased in sophistication, specially in the way drivers and passengers interact with their vehicles. For example, the BMW 7 series driver-controlled systems, contains over 700 functions. Whereas, it makes easier to navigate streets, talk on phone and more, this may lead to visual distraction, since when paying attention to a task not driving related, the brain focus on that activity. That distraction is, according to studies, the third cause of accidents, only surpassed by speeding and drunk driving. Driver distraction is stressed as the main concern by regulators, in particular, National Highway Transportation Safety Agency (NHTSA), which is developing recommended limits for the amount of time a driver needs to spend glancing away from the road to operate in-car features. Diverting attention from driving can be fatal; therefore, automakers have been challenged to design safer and comfortable human-machine interfaces (HMIs) without missing the latest technological achievements. This dissertation aims to mitigate driver distraction by developing a gestural recognition system that allows the user a more comfortable and intuitive experience while driving. The developed system outlines the algorithms to recognize gestures using the capacitive technology.Impulsionados pelos avanços tecnológicos, os automóveis tem de forma continua aumentado em complexidade, sobretudo na forma como os conductores e passageiros interagem com os seus veículos. Por exemplo, os sistemas controlados pelo condutor do BMW série 7 continham mais de 700 funções. Embora, isto facilite a navegação entre locais, falar ao telemóvel entre outros, isso pode levar a uma distração visual, já que ao prestar atenção a uma tarefa não relacionados com a condução, o cérebro se concentra nessa atividade. Essa distração é, de acordo com os estudos, a terceira causa de acidentes, apenas ultrapassada pelo excesso de velocidade e condução embriagada. A distração do condutor é realçada como a principal preocupação dos reguladores, em particular, a National Highway Transportation Safety Agency (NHTSA), que está desenvolvendo os limites recomendados para a quantidade de tempo que um condutor precisa de desviar o olhar da estrada para controlar os sistemas do carro. Desviar a atenção da conducção, pode ser fatal; portanto, os fabricante de automóveis têm sido desafiados a projetar interfaces homemmáquina (HMIs) mais seguras e confortáveis, sem perder as últimas conquistas tecnológicas. Esta dissertação tem como objetivo minimizar a distração do condutor, desenvolvendo um sistema de reconhecimento gestual que permite ao utilizador uma experiência mais confortável e intuitiva ao conduzir. O sistema desenvolvido descreve os algoritmos de reconhecimento de gestos usando a tecnologia capacitiva.It is worth noting that this work has been financially supported by the Portugal Incentive System for Research and Technological Development in scope of the projects in co-promotion number 036265/2013 (HMIExcel 2013-2015), number 002814/2015 (iFACTORY 2015-2018) and number 002797/2015 (INNOVCAR 2015-2018)

Investigation of the Viscoelastic Effect on Optical- Fiber Sensing and Its Solution for 3D-Printed Sensor Packages

Viscoelasticity is an effect seen in a wide range of materials and it affects the reliability of static measurements made using Fiber Bragg Grating-based sensors, because either the target structure, the adhesive used, or the fiber itself could be viscoelastic. The effect of viscoelasticity on FBG-based sensing has been comprehensively researched through theoretical analysis and simulation using a finite-element approach and a further data processing method to reconstruct the graphical data has been developed. An integrated sensor package comprising of an FBG-based sensor in a polymer host and manufactured by using three-dimensional printing was investigated and examined through tensile testing to validate the approach. The application of the 3D-printed FBG-based sensor package, coupled to the data process method has been explored to monitor the height of a railway pantograph, a critical measurement requirement to monitor elongation, employing a method that can be used in the presence of electromagnetic interference. The results show that the effect of viscoelasticity can be effectively eliminated, and the graphical system response allows results that are sufficiently precise for field use to be generated

Cation Discrimination in Organic Electrochemical Transistors by Dual Frequency Sensing

In this work, we propose a strategy to sense quantitatively and specifically cations, out of a single organic electrochemical transistor (OECT) device exposed to an electrolyte. From the systematic study of six different chloride salts over 12 different concentrations, we demonstrate that the impedance of the OECT device is governed by either the channel dedoping at low frequency and the electrolyte gate capacitive coupling at high frequency. Specific cationic signatures, which originates from the different impact of the cations behavior on the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) polymer and their conductivity in water, allow their discrimination at the same molar concentrations. Dynamic analysis of the device impedance at different frequencies could allow the identification of specific ionic flows which could be of a great use in bioelectronics to further interpret complex mechanisms in biological media such as in the brain.Comment: Full text and supporting informatio

Internet of Things-aided Smart Grid: Technologies, Architectures, Applications, Prototypes, and Future Research Directions

Traditional power grids are being transformed into Smart Grids (SGs) to address the issues in existing power system due to uni-directional information flow, energy wastage, growing energy demand, reliability and security. SGs offer bi-directional energy flow between service providers and consumers, involving power generation, transmission, distribution and utilization systems. SGs employ various devices for the monitoring, analysis and control of the grid, deployed at power plants, distribution centers and in consumers' premises in a very large number. Hence, an SG requires connectivity, automation and the tracking of such devices. This is achieved with the help of Internet of Things (IoT). IoT helps SG systems to support various network functions throughout the generation, transmission, distribution and consumption of energy by incorporating IoT devices (such as sensors, actuators and smart meters), as well as by providing the connectivity, automation and tracking for such devices. In this paper, we provide a comprehensive survey on IoT-aided SG systems, which includes the existing architectures, applications and prototypes of IoT-aided SG systems. This survey also highlights the open issues, challenges and future research directions for IoT-aided SG systems