RF-compass: Robot object manipulation using RFIDs

Modern robots have to interact with their environment, search for objects, and move them around. Yet, for a robot to pick up an object, it needs to identify the object's orientation and locate it to within centimeter-scale accuracy. Existing systems that provide such information are either very expensive (e.g., the VICON motion capture system valued at hundreds of thousands of dollars) and/or suffer from occlusion and narrow field of view (e.g., computer vision approaches). This paper presents RF-Compass, an RFID-based system for robot navigation and object manipulation. RFIDs are low-cost and work in non-line-of-sight scenarios, allowing them to address the limitations of existing solutions. Given an RFID-tagged object, RF-Compass accurately navigates a robot equipped with RFIDs toward the object. Further, it locates the center of the object to within a few centimeters and identifies its orientation so that the robot may pick it up. RF-Compass's key innovation is an iterative algorithm formulated as a convex optimization problem. The algorithm uses the RFID signals to partition the space and keeps refining the partitions based on the robot's consecutive moves.We have implemented RF-Compass using USRP software radios and evaluated it with commercial RFIDs and a KUKA youBot robot. For the task of furniture assembly, RF-Compass can locate furniture parts to a median of 1.28 cm, and identify their orientation to a median of 3.3 degrees.National Science Foundation (U.S.

Array signal processing for source localization and enhancement

“A common approach to the wide-band microphone array problem is to assume a certain array geometry and then design optimal weights (often in subbands) to meet a set of desired criteria. In addition to weights, we consider the geometry of the microphone arrangement to be part of the optimization problem. Our approach is to use particle swarm optimization (PSO) to search for the optimal geometry while using an optimal weight design to design the weights for each particle’s geometry. The resulting directivity indices (DI’s) and white noise SNR gains (WNG’s) form the basis of the PSO’s fitness function. Another important consideration in the optimal weight design are several regularization parameters. By including those parameters in the particles, we optimize their values as well in the operation of the PSO. The proposed method allows the user great flexibility in specifying desired DI’s and WNG’s over frequency by virtue of the PSO fitness function. Although the above method discusses beam and nulls steering for fixed locations, in real time scenarios, it requires us to estimate the source positions to steer the beam position adaptively. We also investigate source localization of sound and RF sources using machine learning techniques. As for the RF source localization, we consider radio frequency identification (RFID) antenna tags. Using a planar RFID antenna array with beam steering capability and using received signal strength indicator (RSSI) value captured for each beam position, the position of each RFID antenna tag is estimated. The proposed approach is also shown to perform well under various challenging scenarios”--Abstract, page iv

Dense and long-term monitoring of Earth surface processes with passive RFID -- a review

Billions of Radio-Frequency Identification (RFID) passive tags are produced yearly to identify goods remotely. New research and business applications are continuously arising, including recently localization and sensing to monitor earth surface processes. Indeed, passive tags can cost 10 to 100 times less than wireless sensors networks and require little maintenance, facilitating years-long monitoring with ten's to thousands of tags. This study reviews the existing and potential applications of RFID in geosciences. The most mature application today is the study of coarse sediment transport in rivers or coastal environments, using tags placed into pebbles. More recently, tag localization was used to monitor landslide displacement, with a centimetric accuracy. Sensing tags were used to detect a displacement threshold on unstable rocks, to monitor the soil moisture or temperature, and to monitor the snowpack temperature and snow water equivalent. RFID sensors, available today, could monitor other parameters, such as the vibration of structures, the tilt of unstable boulders, the strain of a material, or the salinity of water. Key challenges for using RFID monitoring more broadly in geosciences include the use of ground and aerial vehicles to collect data or localize tags, the increase in reading range and duration, the ability to use tags placed under ground, snow, water or vegetation, and the optimization of economical and environmental cost. As a pattern, passive RFID could fill a gap between wireless sensor networks and manual measurements, to collect data efficiently over large areas, during several years, at high spatial density and moderate cost.Comment: Invited paper for Earth Science Reviews. 50 pages without references. 31 figures. 8 table

Advanced Radio Frequency Identification Design and Applications

Radio Frequency Identification (RFID) is a modern wireless data transmission and reception technique for applications including automatic identification, asset tracking and security surveillance. This book focuses on the advances in RFID tag antenna and ASIC design, novel chipless RFID tag design, security protocol enhancements along with some novel applications of RFID

RF-IDraw: virtual touch screen in the air using RF signals

Prior work in RF-based positioning has mainly focused on discovering the absolute location of an RF source, where state-of-the-art systems can achieve an accuracy on the order of tens of centimeters using a large number of antennas. However, many applications in gaming and gesture based interface see more benefits in knowing the detailed shape of a motion. Such trajectory tracing requires a resolution several fold higher than what existing RF-based positioning systems can offer. This paper shows that one can provide a dramatic increase in trajectory tracing accuracy, even with a small number of antennas. The key enabler for our design is a multi-resolution positioning technique that exploits an intrinsic tradeoff between improving the resolution and resolving ambiguity in the location of the RF source. The unique property of this design is its ability to precisely reconstruct the minute details in the trajectory shape, even when the absolute position might have an offset. We built a prototype of our design with commercial off-the-shelf RFID readers and tags and used it to enable a virtual touch screen, which allows a user to interact with a desired computing device by gesturing or writing her commands in the air, where each letter is only a few centimeters wide.Lincoln LaboratoryUnited States. Air Forc

Ultra high frequency (UHF) radio-frequency identification (RFID) for robot perception and mobile manipulation

Personal robots with autonomy, mobility, and manipulation capabilities have the potential to dramatically improve quality of life for various user populations, such as older adults and individuals with motor impairments. Unfortunately, unstructured environments present many challenges that hinder robot deployment in ordinary homes. This thesis seeks to address some of these challenges through a new robotic sensing modality that leverages a small amount of environmental augmentation in the form of Ultra High Frequency (UHF) Radio-Frequency Identification (RFID) tags. Previous research has demonstrated the utility of infrastructure tags (affixed to walls) for robot localization; in this thesis, we specifically focus on tagging objects. Owing to their low-cost and passive (battery-free) operation, users can apply UHF RFID tags to hundreds of objects throughout their homes. The tags provide two valuable properties for robots: a unique identifier and receive signal strength indicator (RSSI, the strength of a tag's response). This thesis explores robot behaviors and radio frequency perception techniques using robot-mounted UHF RFID readers that enable a robot to efficiently discover, locate, and interact with UHF RFID tags applied to objects and people of interest. The behaviors and algorithms explicitly rely on the robot's mobility and manipulation capabilities to provide multiple opportunistic views of the complex electromagnetic landscape inside a home environment. The electromagnetic properties of RFID tags change when applied to common household objects. Objects can have varied material properties, can be placed in diverse orientations, and be relocated to completely new environments. We present a new class of optimization-based techniques for RFID sensing that are robust to the variation in tag performance caused by these complexities. We discuss a hybrid global-local search algorithm where a robot employing long-range directional antennas searches for tagged objects by maximizing expected RSSI measurements; that is, the robot attempts to position itself (1) near a desired tagged object and (2) oriented towards it. The robot first performs a sparse, global RFID search to locate a pose in the neighborhood of the tagged object, followed by a series of local search behaviors (bearing estimation and RFID servoing) to refine the robot's state within the local basin of attraction. We report on RFID search experiments performed in Georgia Tech's Aware Home (a real home). Our optimization-based approach yields superior performance compared to state of the art tag localization algorithms, does not require RF sensor models, is easy to implement, and generalizes to other short-range RFID sensor systems embedded in a robot's end effector. We demonstrate proof of concept applications, such as medication delivery and multi-sensor fusion, using these techniques. Through our experimental results, we show that UHF RFID is a complementary sensing modality that can assist robots in unstructured human environments.PhDCommittee Chair: Kemp, Charles C.; Committee Member: Abowd, Gregory; Committee Member: Howard, Ayanna; Committee Member: Ingram, Mary Ann; Committee Member: Reynolds, Matt; Committee Member: Tentzeris, Emmanoui

Sensors and Systems for Indoor Positioning

This reprint is a reprint of the articles that appeared in Sensors' (MDPI) Special Issue on “Sensors and Systems for Indoor Positioning". The published original contributions focused on systems and technologies to enable indoor applications

Application of Ultra-Wideband Technology to RFID and Wireless Sensors

Aquesta Tesi Doctoral estudia l'ús de tecnologia de ràdio banda ultraampla (UWB) per sistemes de identificació per radiofreqüència (RFID) i sensors sense fils. Les xarxes de sensors sense fils (WSNs), ciutats i llars intel•ligents, i, en general, l'Internet de les coses (IoT) requereixen interfícies de ràdio simples i de baix consum i cost per un número molt ampli de sensors disseminats. UWB en el domini temporal es proposa aquí com una tecnologia de radio habilitant per aquestes aplicacions. Un model circuital s'estudia per RFID d'UWB codificat en el temps. Es proposen lectors basats en ràdars polsats comercials amb tècniques de processat de senyal. Tags RFID sense xip (chipless) codificats en el temps son dissenyats i caracterizats en termes de número d'identificacions possible, distància màxima de lectura, polarització, influència de materials adherits, comportament angular i corbatura del tag. Es proposen sensors chipless de temperatura i composició de ciment (mitjançant detecció de permitivitat). Dos plataformes semipassives codificades en temps (amb un enllaç paral•lel de banda estreta per despertar el sensor i estalviar energia) es proposen com solucions més complexes i robustes, amb una distància de lectura major. Es dissenya un sensor de temperatura (alimentat per energia solar) i un sensor de diòxid de nitrogen (mitjançant nanotubs de carboni i alimentat per una petita bateria), ambdòs semipassius amb circuiteria analògica. Es dissenya un multi-sensor semipassiu capaç de mesurar temperatura, humitat, pressió i acceleració, fent servir un microcontrolador de baix consum digital. Combinant els tags RFID UWB codificats en temps amb tecnologia de ràdar de penetració del terra (GPR), es deriva una aplicació per localització en interiors amb terra intel•ligent. Finalment, dos sistemes actius RFID UWB codificats en el temps s'estudien per aplicacions de localització de molt llarg abast.Esta Tesis Doctoral estudia el uso de tecnología de radio de banda ultraancha (UWB) para sistemas de identificación por radiofrecuencia (RFID) y sensores inalámbricos. Las redes de sensores inalámbricas (WSNs), ciudades y casas inteligentes, y, en general, el Internet de las cosas (IoT) requieren de interfaces de radio simples y de bajo consumo y coste para un número muy amplio de sensores diseminados. UWB en el dominio temporal se propone aquí como una tecnología de radio habilitante para dichas aplicaciones. Un modelo circuital se estudia para RFID de UWB codificado en tiempo. Configuraciones de lector, basadas en rádar pulsados comerciales, son propuestas, además de técnicas de procesado de señal. Tags RFID sin chip (chipless) codificados en tiempo son diseñados y caracterizados en términos de número de identificaciones posible, distancia máxima de lectura, polarización, influencia de materiales adheridos, comportamiento angular y curvatura del tag. Se proponen sensores chipless de temperatura y composición de cemento (mediante detección de permitividad). Dos plataformas semipasivas codificadas en tiempo (con un enlace paralelo de banda estrecha para despertar el sensor y ahorrar energía) se proponen como soluciones más complejas y robustas, con una distancia de lectura mayor. Se diseña un sensor de temperatura (alimentado por energía solar) y un sensor de dióxido de nitrógeno (mediante nanotubos de carbono y alimentado por una batería pequeña), ambos semipasivos con circuitería analógica. Se diseña un multi-sensor semipasivo capaz de medir temperatura, humedad, presión y aceleración, usando un microcontrolador digital de bajo consumo. Combinando los tags RFID UWB codificados en tiempo y tecnología de radar de penetración de suelo (GPR), se deriva una aplicación para localización en interiores con suelo inteligente. Finalmente, dos sistemas activos RFID UWB codificados en tiempo se estudian para aplicaciones de localización de muy largo alcance.This Doctoral Thesis studies the use of ultra-wideband (UWB) radio technology for radio-frequency identification (RFID) and wireless sensors. Wireless sensor networks (WSNs) for smart cities, smart homes and, in general, Internet of Things (IoT) applications require low-power, low-cost and simple radio interfaces for an expected very large number of scattered sensors. UWB in time domain is proposed here as an enabling radio technology. A circuit model is studied for time-coded UWB RFID. Reader setups based on commercial impulse radars are proposed, in addition to signal processing techniques. Chipless time-coded RFID tags are designed and characterized in terms of number of possible IDs, maximum reading distance, polarization, influence of attached materials, angular behaviour and bending. Chipless wireless temperature sensors and chipless concrete composition sensors (enabled by permittivity sensing) are proposed. Two semi-passive time-coded RFID sensing platforms are proposed as more complex, more robust, and longer read-range solutions. A wake-up link is used to save energy when the sensor is not being read. A semi-passive wireless temperature sensor (powered by solar energy) and a wireless nitrogen dioxide sensor (enabled with carbon nanotubes and powered by a small battery) are developed, using analog circuitry. A semi-passive multi-sensor tag capable of measuring temperature, humidity, pressure and acceleration is proposed, using a digital low-power microcontroller. Combining time-coded UWB RFID tags and ground penetrating radar, a smart floor application for indoor localization is derived. Finally, as another approach, two active time-coded RFID systems are developed for very long-range applications

1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance

Beam scanning by liquid-crystal biasing in a modified SIW structure

A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium