Range-Only Node Localization: The Arbitrary Anchor Case In D-Dimensions

This work is situated at the intersection of two large fields of research the Localization problem and applications in Wireless Networks. We are interested in providing good estimations for network node locations in a defined space based on sensor measurements. Many methods have being created for the localization problem, in special we have the classical Triangulation and Trilateration procedures and MultiDimensional Scaling. A more recent method, DILOC, utilizes barycentric coordinates in order to simplify part of the non-linearities inherent to this problem. Except for Triangulation in which we require angle measurements between nodes, the other cited methodologies require, typically only, range measurements. Off course, there exists variants which allow the use of range and angle measurements. We specialize our interest in range only methods utilizing barycentric coordinates by first providing a novel way to compute barycentric coordinates for any possible node-neighbor spatial configuration in any given dimension. Which, we use as basis for our experiments with averaging processes and the development of our centralized and distributed gradient descent algorithms. Our distributed algorithm is able to receive range measurements with noise of uncharacterized distributions as it inputs. Using simulations in Matlab, we provide comparisons of our algorithms with Matlab\u27s MDS function. Lastly, we show our efforts on providing a physical network implementation utilizing existing small form factor computers, wireless communication modules and range sensors

Localización y autocalibrado simultáneo con sistemas de posicionamiento local ultrasónicos

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Localización y autocalibrado simultáneo con sistemas de posicionamiento local ultrasónicos

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Low Mobility Cable Robot with Application to Robotic Warehousing

Cable-based robots consist of a rigid mobile platform connected via flexible links (cables, wires, tendons) to a surrounding static platform. The use of cables simplifies the mechanical structure and reduces the inertia, allowing the mobile platform to reach high motion acceleration in large workspaces. These attributes give, in principle, an advantage over conventional robots used for industrial applications, such as the pick and place of objects inside factories or similar exterior large workspaces. However, unique cable properties involve new theoretical and technical challenges: all cables must be in tension to avoid collapse of the mobile platform. In addition, positive tensions applied to cables may affect the overall stiffness, that is, cable stretch might result in unacceptable oscillations of the mobile platform. Fully constrained cable-based robots can be distinguished from other types of cable-based robots because the motion and force generation of the mobile platform is accomplished by controlling both the cable lengths and the positive cable tensions. Fully constrained cable-based robots depend on actuator redundancy, that is, the addition of one or more actuated cables than end-effector degrees of freedom. Redundancy has proved to be beneficial to expand the workspace, remove some types of singularities, increase the overall stiffness, and support high payloads in several proposed cable-based robot designs. Nevertheless, this strategy demands the development of efficient controller designs for real-time applications. This research deals with the design and control of a fully constrained cable-based parallel manipulator for large-scale high-speed warehousing applications. To accomplish the design of the robot, a well-ordered procedure to analyze the cable tensions, stiffness and workspace will be presented to obtain an optimum structure. Then, the control problem will be investigated to deal with the redundancy solution and all-positive cable tension condition. The proposed control method will be evaluated through simulation and experimentation in a prototype manufactured for testing

Advances in Robot Kinematics : Proceedings of the 15th international conference on Advances in Robot Kinematics

International audienceThe motion of mechanisms, kinematics, is one of the most fundamental aspect of robot design, analysis and control but is also relevant to other scientific domains such as biome- chanics, molecular biology, . . . . The series of books on Advances in Robot Kinematics (ARK) report the latest achievement in this field. ARK has a long history as the first book was published in 1991 and since then new issues have been published every 2 years. Each book is the follow-up of a single-track symposium in which the participants exchange their results and opinions in a meeting that bring together the best of world’s researchers and scientists together with young students. Since 1992 the ARK symposia have come under the patronage of the International Federation for the Promotion of Machine Science-IFToMM.This book is the 13th in the series and is the result of peer-review process intended to select the newest and most original achievements in this field. For the first time the articles of this symposium will be published in a green open-access archive to favor free dissemination of the results. However the book will also be o↵ered as a on-demand printed book.The papers proposed in this book show that robot kinematics is an exciting domain with an immense number of research challenges that go well beyond the field of robotics.The last symposium related with this book was organized by the French National Re- search Institute in Computer Science and Control Theory (INRIA) in Grasse, France

Coordinate-free Formulation of a 3-2-1 Wire-based Tracking Device using Cayley-Menger Determinants

This paper deals with the problem of estimating the pose of a rigid moving object by measuring the length of six wires attached to it. Among all possible locations for the attachments on the moving object, the "3-2-1" configuration exhibits the highest number of favorable properties. A closed-form coordinate-free solution to the forward kinematics of this particular configuration is given in terms of Cayley-Menger determinants. The proposed formulation is mathematically more tractable compared to previous ones because all terms are determinants with geometric meaning. This accommodates a more thorough investigation of the properties of the device and leads to formulas whose numerical conditioning is independent from the chosen reference frames

Recent Advances in Indoor Localization Systems and Technologies

Despite the enormous technical progress seen in the past few years, the maturity of indoor localization technologies has not yet reached the level of GNSS solutions. The 23 selected papers in this book present the recent advances and new developments in indoor localization systems and technologies, propose novel or improved methods with increased performance, provide insight into various aspects of quality control, and also introduce some unorthodox positioning methods

Visible light indoor positioning for mobile robots

Mestrado em Engenharia Eletrónica e TelecomunicaçõesEsta dissertação investiga a localização em espaços interiores através da comunicação por luz visível para robôs móveis, com base nos LEDs fixos nos edifícios, dando particular atenção à simulação e desenho do sensor, com vista ao desenvolvimento de um sensor de localização. Explica-se o crescimento da tecnologia LED e da constante necessidade de localização do homem em espaços interiores. Apresentado algumas características do LED e dos foto-detetores existentes. Com uma breve referencia a algumas das comunicações por luz visível de baixo débito possíveis de implementar. O desenvolvimento do protótipo do sensor inicia-se, principalmente, pela simulação de alguns dispositivos essenciais e das suas caraterísticas, como o emissor LED no controlo do ^angulo de meia potência (HPA) e a altura a que se encontra, e no recetor foto-díodo e a sua restrição de campo de visão (FOV). Simula-se o sensor pretendido com o número de foto-díodos necessários otimizando o espaço físico disponível e fazendo não só um refinamento no FOV mas também na distribuição espacial dos foto-díodos com funções predefinidas para a redução de incertezas de decisão de localização do robô. Estes resultados permitiram a construção física do sensor, desde o suporte para os foto-díodos, tendo em conta todas as medidas durante as simulações, e terminando com o desenvolvimento dos sensores e a sua integração completa. O tratamento de dados da leitura dos sinais recebidos do sensor são tratados por um microcontrolador, permitindo calcular parâmetros fundamentais no cálculo da posição. No final, os resultados teóricos bem como os práticos obtidos ao longo do desenvolvimento e possíveis propostas para trabalhos futuros que beneficiam desta investigaçãoThis dissertation investigates indoor localization through visible light communication for mobile robots, based on Light Emitting Diode (LED)s fixed on buildings, giving particular focus to sensor's design and simulation, with the goal of developing a localization sensor. Its explains the growth of LED technology and the constant need of location of man in indoor spaces. Presenting some LED character and existent photodetector features. With a brief overview of the low debit Visible Light Communication (VLC) architectures. The sensor's prototype development begins, mainly, by the simulation of some essential device and its features like the control of Half Power Angle (HPA) by the emitter LED and its height and also the Field Of View (FOV) restriction by the receiver photodiode. The target sensor is simulated with the necessary number of photodiodes optimizing the physical area available and its made a refinement not only in FOV but also in spacial distribuition of the photodiodes with predefined functions to reduce localization uncertanty within robot's decision. This procedure allows the uncertainty reduction associated with the robot's positioning decision and delivers the global field of view integration of all the photodiodes. The results allowed the physical construction of the sensor, starting with the photodiodes support structure, taking into account all the measures collected during simulation, and finishing with the sensors development and its full integration. The data treatment of the received signals by the sensor is done by a microcontroller, granting the position calculation using fundamental parameters operations. In the end, the theoretical as well as the practical results obtained are presented and also possible future projects that can bennefit from this investigation

Ahlfors circle maps and total reality: from Riemann to Rohlin

This is a prejudiced survey on the Ahlfors (extremal) function and the weaker {\it circle maps} (Garabedian-Schiffer's translation of "Kreisabbildung"), i.e. those (branched) maps effecting the conformal representation upon the disc of a {\it compact bordered Riemann surface}. The theory in question has some well-known intersection with real algebraic geometry, especially Klein's ortho-symmetric curves via the paradigm of {\it total reality}. This leads to a gallery of pictures quite pleasant to visit of which we have attempted to trace the simplest representatives. This drifted us toward some electrodynamic motions along real circuits of dividing curves perhaps reminiscent of Kepler's planetary motions along ellipses. The ultimate origin of circle maps is of course to be traced back to Riemann's Thesis 1851 as well as his 1857 Nachlass. Apart from an abrupt claim by Teichm\"uller 1941 that everything is to be found in Klein (what we failed to assess on printed evidence), the pivotal contribution belongs to Ahlfors 1950 supplying an existence-proof of circle maps, as well as an analysis of an allied function-theoretic extremal problem. Works by Yamada 1978--2001, Gouma 1998 and Coppens 2011 suggest sharper degree controls than available in Ahlfors' era. Accordingly, our partisan belief is that much remains to be clarified regarding the foundation and optimal control of Ahlfors circle maps. The game of sharp estimation may look narrow-minded "Absch\"atzungsmathematik" alike, yet the philosophical outcome is as usual to contemplate how conformal and algebraic geometry are fighting together for the soul of Riemann surfaces. A second part explores the connection with Hilbert's 16th as envisioned by Rohlin 1978.Comment: 675 pages, 199 figures; extended version of the former text (v.1) by including now Rohlin's theory (v.2