A comprehensive dynamic model for class-1 tensegrity systems based on quaternions

In this paper we propose a new dynamic model, based on quaternions, for tensegrity systems of class-1. Quaternions are used to represent orientations of a rigid body in the 3-dimensional space eliminating the problem of singularities. Moreover, the equations based on quaternions allow to perform more precise calculations and simulations because they do not use trigonometric functions for the representation of angles. We present a thorough introduction of tensegrities and the current state of research. We also introduce the quaternions and provide in the appendix some important details and useful properties. Applying the Euler–Lagrange approach we derive a comprehensive dynamic model, first for a simple rigid bar in the space and, at last, for a class-1 tensegrity system. We present two model forms: a matrix and a vectorial form. The first more compact and easier to write, the latter more suitable to apply the tools and the theory based on vector fields.Postprint (author’s final draft

Map format for mobile robot map-based autonomous navigation

This technical report defines the spatial representation and the map file format used in a mobile robot map-based autonomous navigation system designed to be deployed in urban areas. After a discussion about common requirements of spatial representations for map-based mobile robot autonomous navigation, a proposed environment model that fulfills previously discussed requirements is formally presented. An example of a map representing an outdoor area of an university campus of about 10000m2 is given to better illustrate the map format. Finally, the report shows simulation results on global localization and path planning using the proposed map

A comprehensive dynamic model for class-1 tensegrity systems based on quaternions

a b s t r a c t In this paper we propose a new dynamic model, based on quaternions, for tensegrity systems of class-1. Quaternions are used to represent orientations of a rigid body in the 3-dimensional space eliminating the problem of singularities. Moreover, the equations based on quaternions allow to perform more precise calculations and simulations because they do not use trigonometric functions for the representation of angles. We present a thorough introduction of tensegrities and the current state of research. We also introduce the quaternions and provide in the appendix some important details and useful properties. Applying the Euler-Lagrange approach we derive a comprehensive dynamic model, first for a simple rigid bar in the space and, at last, for a class-1 tensegrity system. We present two model forms: a matrix and a vectorial form. The first more compact and easier to write, the latter more suitable to apply the tools and the theory based on vector fields

Real-time software for mobile robot simulation and experimentation in cooperative environments

Trabajo presentado al 1st SIMPAR celebrado en Venecia del 3 al 6 de noviembre de 2008.This paper presents the software being developed at IRI (Institut de Robotica i Informatica Industrial) for mobile robot autonomous navigation in the context of the European project URUS (Ubiquitous Robots in Urban Settings). In order that a deployed sensor network and robots operating in the environment cooperate in terms of information sharing, main requirements are real-time performance and the integration of information coming from remote machines not onboard the robot. Moreover, the project involves a group of eleven industrial and academic partners, therefore software integration issues are critical. The proposed software framework is based on the YARP middleware and has been tested in real and simulated experiments.This work was supported by projects: 'Ubiquitous networking robotics in urban settings' (E-00938), 'CONSOLIDER-INGENIO 2010 Multimodal interaction in pattern recognition and computer vision' (V-00069), 'Robotica ubicua para entornos urbanos' (J-01225). Partially supported by Consolider Ingenio 2010, project CSD2007-00018, CICYT project DPI2007-61452, and IST-045062 of the European Community Union.Peer Reviewe

On The Structure Of The Objective Function For A Pressure Sensor Placement Optimizing Methodology Based On Genetic Algorithms Applied To Model-Based Leakage Localization In Distribution Water Networks

Real-time monitoring of distribution water networks relies on the deployment of sensors and the availability of their measurements in order to predict the system state and assess its performance. A meaningful application of this methodology is the detection and localization of leaks using model-based approaches. Since the number of sensors is limited because of budget constraints, it is important to place these devices in locations where the effectiveness of the leakage diagnosis is maximized. Finding the best sensor distribution is a global optimization problem defined by an objective function that might depend on different factors. Therefore, deriving the correct structure of such function is a crucial step as a wrong definition would lead towards a confusing optimal solution affecting negatively the monitoring performance. In general, sensor placement optimization methods describe objective functions using factors related to the amount of undistinguishable leaks. More concretely, the methods first compute groups of locations where leaks cannot be differentiated and then maximize this number of groups or minimize their size. In this paper, additional factors are presented to accurately represent the requirements of the leak diagnosis phase. These include other statistical figures related to the size of groups, geographical characteristics like the group’s extension area, levels of sensitivity that indicate whether a location is more or less sensible to pressure changes, etc. The objective of this study is to review several factors in order to comprehend their behaviour and justify or discard them for the objective function. The indicators under study are evaluated by means of a cross-correlation analysis applied to the scenario defined by the District Metered Area of the Barcelona water distribution. Results indicate the existence of different independency levels between the indicators that allow us to select those with less redundancy

Guiding and regrouping people missions in urban areas using cooperative multi-robot task allocation

Peer ReviewedPostprint (author’s final draft

A decision support system for on-line leakage localization

This paper describes a model-driven decision-support system (software tool) implementing a model-based methodology for on-line leakage detection and localization which is useful for a large class of water distribution networks. Since these methods present a certain degree of complexity which limits their use to experts, the proposed software tool focuses on the integration of a method emphasizing its use by water network managers as a decision support system. The proposed software tool integrates a model-based leakage localization methodology based on the use of on-line telemetry information, as well as a water network calibrated hydraulic model. The application of the resulting decision support software tool in a district metered area (DMA) of the Barcelona distribution network is provided and discussed. The obtained results show that the leakage detection and localization may be performed efficiently reducing the required time. © 2014 Elsevier Ltd.The authors wish to thank the support received by the AM0901 project funded by R+i Alliance (Suez Environnement) and by the EFFINET grant FP7-ICT-2012-318556 of the European Commission.Peer Reviewe

Real-time monitoring and control for efficient management of drinking water networks: Barcelona case study

Trabajo presentado a la 11th International Conference on Hydroinformatics celebrada en New York (US) del 17 al 21 de agosto de 2014.This research has been partially funded by the DGR of Generalitat de Catalunya (SAC group Ref. 2009/SGR/1491), Doctorat Industrial AGAUR-2013-DI-041 and by EFFINET: Efficient Integrated Real-time Monitoring and Control of Drinking Water Networks (FP7-ICT2011-8-318556).Peer Reviewe

Autoencoders for Semi-Supervised Water Level Modeling in Sewer Pipes with Sparse Labeled Data

More frequent and thorough inspection of sewer pipes has the potential to save billions in utilities. However, the amount and quality of inspection are impeded by an imprecise and highly subjective manual process. It involves technicians judging stretches of sewer based on video from remote-controlled robots. Determining the state of sewer pipes based on these videos entails a great deal of ambiguity. Furthermore, the frequency with which the different defects occur differs a lot, leading to highly imbalanced datasets. Such datasets represent a poor basis for automating the labeling process using supervised learning. With this paper we explore the potential of self-supervision as a method for reducing the need for large numbers of well-balanced labels. First, our models learn to represent the data distribution using more than a million unlabeled images, then a small number of labeled examples are used to learn a mapping from the learned representations to a relevant target variable, in this case, water level. We choose a convolutional Autoencoder, a Variational Autoencoder and a Vector-Quantised Variational Autoencoder as the basis for our experiments. The best representations are shown to be learned by the classic Autoencoder with the Multi-Layer Perceptron achieving a Mean Absolute Error of 9.93. This is an improvement of 9.62 over the fully supervised baseline.Peer ReviewedPostprint (published version

Optimizing operating rules of multiple source water supply systems in terms of system reliability and resulting operating costs

This Presentation is brought to you for free and open access by the City College of New York at CUNY Academic Works. It has been accepted forinclusion in International Conference on Hydroinformatics by an authorized administrator of CUNY Academic Works. For more information, pleasecontact [email protected] and operation of a multiple-objective multisource water supply system from the point of view of the conjunctive use of water sources is a very complex problem whose solution is not just obtained using analytical models but also through a negotiation process among stakeholders and in which Public Bodies have a main role. For these reasons, this problem has been addressed using conservative approaches based on simulation models or simulation–linear optimization models parameterized using few parameters which, in general, are already covered by existing generalized modelling tools using a longer or shorter trial and error process. However, these conservative approaches have drawbacks and constraints when dealing with certain complexities of water supply systems (i.e.: non-linearity, uncertainty or stochastic nature) that may prevent them of finding an optimal solution. This paper identifies and tests suitable simulation-optimization approaches found in existing generalized modeling tools for optimizing operating rules of multisource water supply systems in terms of system guarantee and resulting operating costs. The main purpose is to find out whether these approaches are already covering the decision support needs of managers, Public Bodies or other stakeholders involved in the operation of these systems, or ‘ad-hoc’ tools may be needed.Peer ReviewedPostprint (published version