Feasible, Robust and Reliable Automation and Control for Autonomous Systems

The Special Issue book focuses on highlighting current research and developments in the automation and control field for autonomous systems as well as showcasing state-of-the-art control strategy approaches for autonomous platforms. The book is co-edited by distinguished international control system experts currently based in Sweden, the United States of America, and the United Kingdom, with contributions from reputable researchers from China, Austria, France, the United States of America, Poland, and Hungary, among many others. The editors believe the ten articles published within this Special Issue will be highly appealing to control-systems-related researchers in applications typified in the fields of ground, aerial, maritime vehicles, and robotics as well as industrial audiences

Manifold interpolation and model reduction

One approach to parametric and adaptive model reduction is via the interpolation of orthogonal bases, subspaces or positive definite system matrices. In all these cases, the sampled inputs stem from matrix sets that feature a geometric structure and thus form so-called matrix manifolds. This work will be featured as a chapter in the upcoming Handbook on Model Order Reduction (P. Benner, S. Grivet-Talocia, A. Quarteroni, G. Rozza, W.H.A. Schilders, L.M. Silveira, eds, to appear on DE GRUYTER) and reviews the numerical treatment of the most important matrix manifolds that arise in the context of model reduction. Moreover, the principal approaches to data interpolation and Taylor-like extrapolation on matrix manifolds are outlined and complemented by algorithms in pseudo-code.Comment: 37 pages, 4 figures, featured chapter of upcoming "Handbook on Model Order Reduction

Linear Regression Models Applied to Imperfect Information Spacecraft Pursuit-evasion Differential Games

Within satellite rendezvous and proximity operations lies pursuit-evasion differential games between two spacecraft. The extent of possible outcomes can be mathematically bounded by differential games where each player employs optimal strategies. A linear regression model is developed from a large data set of optimal control solutions. The model is shown to map pursuer relative starting positions to final capture positions and estimate capture time. The model is 3.8 times faster than the indirect heuristic method for arbitrary pursuer starting positions on an initial relative orbit about the evader. The linear regression model is shown to be well suited for on-board implementation for autonomous mission planning

Sensitivity analysis of uncertain dynamic systems using set-valued integration

We present an extension of set-valued integration to enable efficient sensitivity analysis of parameter-dependent ordinary differential equation (ODE) systems, using both the forward and adjoint methods. The focus is on continuous-time set-valued integration, whereby auxiliary ODE systems are derived whose solutions describe high-order inclusions of the parametric trajectories in the form of polynomial models. The forward and adjoint auxiliary ODE systems treat the parameterization error of the original differential variables as a time-varying uncertainty, and propagate the sensitivity bounds forward and backward in time, respectively. This construction enables building on the sensitivity analysis capabilities of state-of-the-art solvers, such as CVODES in the SUNDIALS suite. Several numerical case studies are presented to assess the performance and accuracy of these set-valued sensitivity integrators

System- and Data-Driven Methods and Algorithms

An increasing complexity of models used to predict real-world systems leads to the need for algorithms to replace complex models with far simpler ones, while preserving the accuracy of the predictions. This two-volume handbook covers methods as well as applications. This first volume focuses on real-time control theory, data assimilation, real-time visualization, high-dimensional state spaces and interaction of different reduction techniques

Spectral and High Order Methods for Partial Differential Equations ICOSAHOM 2018

This open access book features a selection of high-quality papers from the presentations at the International Conference on Spectral and High-Order Methods 2018, offering an overview of the depth and breadth of the activities within this important research area. The carefully reviewed papers provide a snapshot of the state of the art, while the extensive bibliography helps initiate new research directions

On-line path planning and robust adaptive path following for underactuated autonomous underwater vehicles

Autonome Unterwasservehikel (AUV) sind für den Einsatz in maritimen Gebieten mit harschen und lebensbedrohlichen Umgebungsbedingungen sowie langen Missionshorizonten unerlässlich. Die Planung solcher Missionen erfolgt dabei oft über einen übergeordneten Missionsplanungsalgorithmus, der auf Grundlage von Umgebungsdaten, wie z.B. Wetter-, Karten- und Sensordaten, Referenzwegpunkte generiert. Aufgrund zeitlich veränderlicher Missionsziele und dynamisch variierender Hindernisse, wie z.B. andere Seefahrzeuge, ist eine flexible Anpassung dieser Referenzwegpunkte zur Laufzeit unvermeidlich. Da in den meisten Anwendungsfällen eine möglichst genaue Durchquerung der Wegpunkte mit vertretbarem Stellaufwand gewünscht ist, fokussiert diese Dissertation auf die Bahnführung von AUV, die durch eine Kombination aus on-line Bahnplanung und nichtlinearen Folgeregelungskonzepten besteht. Wegen der Anforderungen von Folgeregelungen an die Glattheit der Referenzbahn (C2) werden im ersten Teil dieser Arbeit zunächst 3D Bahnplanungsalgorithmen auf Basis von Polynomen 5. Grades vorgestellt, welche die von der Missionsplanung vorgegebenen Wegpunkte interpolieren. Zur Verbesserung der numerischen Eigenschaften sowie der Reduzierung des Rechenaufwands wird dieser Ansatz auf B-Splines übertragen. Durch eine spezielle Pufferung/Fensterung einer bestimmten Anzahl an Wegpunkten wird die zusätzliche Anforderung an die on-line Planung adressiert. Im zweiten Teil der Arbeit werden ausgehend von einer eingehenden mathematischen Modellbildung von AUVs nichtlineare Folgeregelungskonzepte für den vollaktuierten und den unteraktuierten Fall (mehr Freiheitsgrade als Stellgrößen) entwickelt. Für ersteren wird eine Feedback-Linearisierung mit beobachterbasiertem Ansatz und aktiver Störunterdrückung präsentiert. Für den zweiten Fall wird ein robustes, adaptives Regelgesetz zur Kompensation von Modellunsicherheiten und Störungen entworfen. Wegen der Unteraktuierung des Systems, stellt dies eine anspruchsvolle Aufgabe dar, welche basierend auf der direkten Methode von Lyapunov und adaptiver Backstepping-Verfahren gelöst wird. Zur Robustifizierung des adaptiven Reglers kommen Parameter-Projektions-Techniken zum Einsatz. Abschließend werden formale Nachweise der Stabilität der präsentierten Regelungen angeführt und die Leistungsfähigkeit der entwickelten Ansätze anhand von detaillierten Simulationen belegt.Autonomous underwater vehicles (AUVs) are indispensable for use in maritime areas with harsh and life-threatening environmental conditions as well as long mission horizons. The planning of such missions is often carried out via a generic mission planning algorithm. Based on environmental data, e.g. weather, map and sensor data, it generates position reference points or so-called way-points to be followed by the AUV. Due to time-varying mission objectives and dynamically varying obstacles, such as other maritime vehicles, a flexible on-line adaptation of these way-points is unavoidable. In addition, for most applications an accurate crossing of way-points is desirable. Therefore, this dissertation focuses on the path generation and following of AUVs, which consists of a combination of on-line path planning and nonlinear path following concepts. Due to the special requirements for path following controllers on the smoothness of the reference path (C2), in the first part of this thesis, we present a 3D path planning algorithm based on degree 5 polynomials which interpolates the way-points given by the mission planning. In order to improve the numerical properties and to reduce the computational effort, this approach is transferred to B-splines. Using a special buffering/windowing of a certain number of way-points, the additional requirement on the on-line planning is addressed. In the second part of the thesis, mathematical modeling of AUVs is carried out. Based on that, nonlinear path following control concepts for the fully-actuated and the under actuated case (more degrees of freedom than control inputs) are developed. For the former, a feedback linearization controller with an observer-based approach and active disturbance rejection capabilities is presented. For the second case, a robust, adaptive control law is developed for the compensation of modeling uncertainty and disturbances. Owing to the under actuation of the system, the controller design is a challenging task, which is solved based on the direct method of Lyapunov and adaptive backstepping techniques. Moreover, parameter projection is used to robustify the adaptive controller. Finally, formal proofs of the stability of the presented controllers are provided and the performance of the developed approaches is demonstrated by means of detailed simulations

Applications of Mathematical Models in Engineering

The most influential research topic in the twenty-first century seems to be mathematics, as it generates innovation in a wide range of research fields. It supports all engineering fields, but also areas such as medicine, healthcare, business, etc. Therefore, the intention of this Special Issue is to deal with mathematical works related to engineering and multidisciplinary problems. Modern developments in theoretical and applied science have widely depended our knowledge of the derivatives and integrals of the fractional order appearing in engineering practices. Therefore, one goal of this Special Issue is to focus on recent achievements and future challenges in the theory and applications of fractional calculus in engineering sciences. The special issue included some original research articles that address significant issues and contribute towards the development of new concepts, methodologies, applications, trends and knowledge in mathematics. Potential topics include, but are not limited to, the following: Fractional mathematical models; Computational methods for the fractional PDEs in engineering; New mathematical approaches, innovations and challenges in biotechnologies and biomedicine; Applied mathematics; Engineering research based on advanced mathematical tools

Proceedings of the ECCOMAS Thematic Conference on Multibody Dynamics 2015

This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: ● Formulations and Numerical Methods ● Efficient Methods and Real-Time Applications ● Flexible Multibody Dynamics ● Contact Dynamics and Constraints ● Multiphysics and Coupled Problems ● Control and Optimization ● Software Development and Computer Technology ● Aerospace and Maritime Applications ● Biomechanics ● Railroad Vehicle Dynamics ● Road Vehicle Dynamics ● Robotics ● Benchmark ProblemsPostprint (published version