Geometric Surface-Based Tracking Control of a Quadrotor UAV

New quadrotor UAV control algorithms are developed, based on nonlinear surfaces composed of tracking errors that evolve directly on the nonlinear configuration manifold, thus inherently including in the control design the nonlinear characteristics of the SE(3) configuration space. In particular, geometric surface-based controllers are developed and are shown, through rigorous stability proofs, to have desirable almost global closed loop properties. For the first time in regards to the geometric literature, a region of attraction independent of the position error is identified and its effects are analyzed. The effectiveness of the proposed "surface based" controllers are illustrated by simulations of aggressive maneuvers in the presence of disturbances and motor saturation.Comment: 2018 26th Mediterranean Conference on Control and Automation (MED

Ground Extraction from 3D Lidar Point Clouds

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works Pomares, A., Martínez, J.L., Mandow, A., Martínez, M.A., Morán, M., Morales, J. Ground extraction from 3D lidar point clouds with the Classification Learner App (2018) 26th Mediterranean Conference on Control and Automation, Zadar, Croatia, June 2018, pp.400-405. DOI: PendingGround extraction from three-dimensional (3D) range data is a relevant problem for outdoor navigation of unmanned ground vehicles. Even if this problem has received attention with specific heuristics and segmentation approaches, identification of ground and non-ground points can benefit from state-of-the-art classification methods, such as those included in the Matlab Classification Learner App. This paper proposes a comparative study of the machine learning methods included in this tool in terms of training times as well as in their predictive performance. With this purpose, we have combined three suitable features for ground detection, which has been applied to an urban dataset with several labeled 3D point clouds. Most of the analyzed techniques achieve good classification results, but only a few offer low training and prediction times.This work was partially supported by the Spanish project DPI 2015- 65186-R. The publication has received support from Universidad de Málaga, Campus de Excelencia Andalucía Tech

Obstacle detection algorithm of low computational cost for Guanay II AUV

Obstacle detection is one of the most important stages in the obstacle avoidance system. This work is focused to explain the operation of a designed and implemented for the overall detection of objects with low computational cost strategy. This strategy of low computational cost is based on performing a spatial segmentation of the information obtained by the SONAR and determine the minimum distance between the SONAR (AUV) and the obstacle.Postprint (published version

Scan matching by cross-correlation and differential evolution

Scan matching is an important task, solved in the context of many high-level problems including pose estimation, indoor localization, simultaneous localization and mapping and others. Methods that are accurate and adaptive and at the same time computationally efficient are required to enable location-based services in autonomous mobile devices. Such devices usually have a wide range of high-resolution sensors but only a limited processing power and constrained energy supply. This work introduces a novel high-level scan matching strategy that uses a combination of two advanced algorithms recently used in this field: cross-correlation and differential evolution. The cross-correlation between two laser range scans is used as an efficient measure of scan alignment and the differential evolution algorithm is used to search for the parameters of a transformation that aligns the scans. The proposed method was experimentally validated and showed good ability to match laser range scans taken shortly after each other and an excellent ability to match laser range scans taken with longer time intervals between them.Web of Science88art. no. 85

Nemlineáris dinamikus rendszerek analízis alapú irányítása = Analysis-based control of nonlinear dynamical systems

Rövid összefoglaló Nemlineáris dinamikus rendszerek analízisének és irányításának területén folytattunk kutatásokat. Az analízis eredményeit különböző irányítási célokat megvalósító szabályozási struktúrák tervezéséhez használtuk fel. 1. Nemlineáris dinamikus rendszerek analízise és identifikációja Gráfelméletti megközelítésen alapuló módszert adtunk arra, hogy differenciál-algebrai rendszermodellek egyszerűsítése során hogyan kaphatunk 1-es indexű modellt eredményül. Kapcsolatot találtunk kvázipolinomiális (QP) rendszerek globális stabilitása és lokális disszipatív hamiltoni leírása között. Polinomiális idejű algoritmust adtunk QP rendszerek invariánsainak a modellegyenletekből történő visszanyerésére. Megmutattuk, hogy a lineárisan független reakcióvektorokkal rendelkező reverzibilis reakcióhálózatok egyensúlyi pont körüli lokális disszipatív hamiltoni struktúrával rendelkeznek. Nyomottvizes reaktorok primerköri dinamikáját identifikáltuk a modell részrendszerekre történő szétválasztása alapján. 2. Nemlineáris dinamikus rendszerek irányítása Bilineáris mátrixegyenlőtlenség megoldására vezető stabilizáló visszacsatolást terveztünk QP rendszerekre. A terhelőnyomaték on-line becslését is tartalmazó adaptív referenciakövető szabályozót terveztünk kisteljesítményű gázturbuna modelljére. Az identifikált atomerőművi primerköri modellre az előírt korlátozásokat betartó modell-prediktív szabályozókat terveztünk. Kétszintű szabályozót terveztünk gépjárművek aktív felfüggesztéséhez. | Short summary An interdisciplinary research has been conducted in the field of analysis and control of nonlinear dynamical systems. The results of the analysis have been used to design feedback structures for different control goals. 1. Analysis and identification of nonlinear dynamical systems A method based on graph theory has been proposed for the construction of index-1 models during model simplification. Connections have been found between the global stability and local dissipative-Hamiltonian description of quasi-polynomial (QP) systems. A polynomial time algorithm has been worked out for obtaining invariants of QP systems from the model equations. It has been shown that reversible reaction networks with independent reaction vectors possess a local dissipative Hamiltonian structure around the equilibrium point. The identification of the primary circuit dynamics of pressurized water reactors have been carried out based on the decomposition of the overall model. 2. Control of nonlinear dynamical systems Stabilizing feedback has been computed for QP systems that leads to the solution of a bilinear matrix inequality. An adaptive reference tracking controller has been designed for a low power gas turbine that contains the on-line estimation of the load torque. Model-predictive controllers have been designed for the identified primary circuit dynamics that satisfy the predefined constraints. A two-level controller has been designed for the active suspension of road vehicles

Green buildings and design for adaptation: strategies for renovation of the built environment

The recent EU Directives 2010/31 and 2012/27 provide standards of nearly zero energy buildings for new constructions, aiming at a better quality of the built environment through the adoption of high-performance solutions. In the near future, cities are expected to be the main engine of development while bearing the impact of population growth: new challenges such as increasing energy efficiency, reducing maintenance costs of buildings and infrastructures, facing the effects of climate change and adjusting on-going and future impacts, require smart and sustainable approaches. To improve the capability of adaptation to dynamics of transformation, buildings and districts have to increase their resilience, assumed as ‘the capacity to adapt to changing conditions and to maintain or regain functionality and vitality in the face of stress or disturbance’ (Wilson A., Building Resilience in Boston, Boston Society of Architects, 2013). This paper describes the research methodology, developed by the Department of Architecture, a research unit of Technology for Architecture, to perform the assessment of resilience of existing buildings, as well as the outcomes of its application within Bologna urban context. This methodology focuses on the design for adaptation of social housing buildings, aiming at predicting their expected main impacts (energy consumption, emissions, efficiency, urban quality and environmental sustainability) and at developing models for renovation

BIMing the architectural curricula: integrating Building Information Modelling (BIM) in architectural education

Building Information Modelling (BIM) reflects the current heightened transformation within the Architectural, Engineering and Construction (AEC) Industry and the Facilities and Management (FM) sector, offering a host of benefits from increased efficiency, accuracy, speed, co-ordination, consistency, energy analysis, project cost reduction etc to various stake holders from owners to architects, engineers, contractors and other built environment professionals. Many countries around the world are responding to this paradigm shift including the United Kingdom (UK). The Cabinet office took the decision in 2011 to make the use of collaborative 3D BIM technology mandatory for all public sector construction contracts by 2016 (Cabinet Office, 2011). According to Smith and Tardif, despite certain myths and misconceptions surrounding BIM, its rate of implementation has been much faster in comparison to the availability of professionals skilled in use of BIM, thus creating a skill gap in the design and construction industry (Smith and Tardif, cited in Barison and Santos, 2010a). This article aims at bridging the gap between the graduate skill sets and the changing needs of the profession. The research methodology adopted consists of thoroughly reviewing the existing literature in this subject area coupled with carrying out a survey of accredited Schools of Architecture in the UK. The analysis of the survey questionnaire results shows the extent to which BIM is currently being taught and identifies the barriers where its implementation has either been slow or not yet started. The paper highlights the fact that there has been considerable delay in the successful integration of BIM in the Schools of Architecture in the UK, thus emphasising the need for expeditiously training and preparing students in the use of BIM making them ready to effectively perform in a BIM enabled work arena

Unmanned Aerial Systems for Wildland and Forest Fires

Wildfires represent an important natural risk causing economic losses, human death and important environmental damage. In recent years, we witness an increase in fire intensity and frequency. Research has been conducted towards the development of dedicated solutions for wildland and forest fire assistance and fighting. Systems were proposed for the remote detection and tracking of fires. These systems have shown improvements in the area of efficient data collection and fire characterization within small scale environments. However, wildfires cover large areas making some of the proposed ground-based systems unsuitable for optimal coverage. To tackle this limitation, Unmanned Aerial Systems (UAS) were proposed. UAS have proven to be useful due to their maneuverability, allowing for the implementation of remote sensing, allocation strategies and task planning. They can provide a low-cost alternative for the prevention, detection and real-time support of firefighting. In this paper we review previous work related to the use of UAS in wildfires. Onboard sensor instruments, fire perception algorithms and coordination strategies are considered. In addition, we present some of the recent frameworks proposing the use of both aerial vehicles and Unmanned Ground Vehicles (UV) for a more efficient wildland firefighting strategy at a larger scale.Comment: A recent published version of this paper is available at: https://doi.org/10.3390/drones501001