Search

Self-assembling robots have the potential to undergo autonomous morphological adaptation. However, due to the simplicity in their hardware makeup and their limited perspective of the environment, self-assembling robots are often not able to reach their potential and adapt their morphologies to tasks or environments without external cues or prior information. In this paper, we present supervised morphogenesis — a control methodology that makes self-assembling robots truly flexible by enabling aerial robots to exploit their elevated position and better view of the environment to initiate and control (hence supervise) morphology formation on the ground. We present results of two case studies in which we assess the feasibility of the presented methodology using real robotic hardware. In the case studies, we implemented supervised morphogenesis using two different aerial platforms and up to six self-assembling autonomous robots. We furthermore quantify the benefits attainable for self-assembling robots through cooperation with aerial robots using simulation-based studies. The research presented in this paper is a significant step towards realizing the true potential of self-assembling robots by enabling autonomous morphological adaptation to a priori unknown tasks and environments., SCOPUS: ar.j, info:eu-repo/semantics/published

El siguiente trabajo describe el proceso de desarrollo de un algoritmo de coordinación y gestión de carga para los robots de la solución de monitoreo robótico FAROMATICS. El sistema total se trata de tres robots que realizan actividades de monitoreo, recolección de datos del medio e interacción con los animales . Para que los robots se muevan libremente por el lugar sin molestar o dañar tanto a animales como a instalaciones, se diseño un sistema de rieles colgantes en los cuales los robots se desplazan. El principal desafío del presente trabajo se basa en generar un algoritmo de control que aproveche al máximo la estuctura actual del sistema, es decir un solo punto de recarga para tres elementos automatas. El unico software de desarrollo utilizado en este proyecto es Simulink, el cual mediante un lenguaje gráfico de bloques permite modelar y simular sistemas de control. En dicho programa, se procedió a generar módulos que simulen el comportamiento de cada uno de los robots, y permitan poner a prueba el algoritmo de control. Para su desarrollo se utilizo una arquitectura basada en maquinas de estados finitas y en las primisas: i) el robot que tenga batería completa cederá su lugar para que cargue quien lo necesite, ii) el robot que posea el nivel más bajo de batería pedirá un lugar de carga al robot con mas batería y iii) un robot solo podra trabajar con batería llena y en caso de necesitarlo será capaz de alterar el movimiento de los robots restantes siempre y cuando ellos tengan carga suficiente. Al final del desarrollo se presentan las graficas obtenidas e simulación y se analizan sus reulados. The following work describes the developing process a coordination and battery management algorithm for the robots of the FAROMATICS robotic monitoring solution. The total system consists of three robots that carry out activities of monitoring, collecting data from the environment and interacting with animals. In order for the robots to move freely around the place without disturbing or damaging both animals and facilities, a hanging rail system was designed on which the robots move. The main challenge of this work is based on generating a control algorithm that makes the most of the current structure of the system, that is, a single recharging point for three automated elements. The only development software used in this project is Simulink, which by means of a graphic block language allows to model and simulate control systems. In this program, we proceeded to generate modules that simulate the behavior of each of the robots, and allow us to test the control algorithm. For its development, an architecture based on finite state machines and on the cousins was used: i) the robot that has a full battery will give up its place to charge whoever needs it, ii) the robot that has the lowest battery level will request a instead of charging the robot with more battery and iii) a robot can only work with a full battery and if needed it will be able to alter the movement of the remaining robots as long as they have enough charge. At the end of the development, the simulation graphs are presented and their reules are analyzed.

Ao observar a situação atual, na qual atos de vandalismo e terrorismo tornaram-se frequentes e cada vez mais presentes ao redor do mundo, principalmente em grandes cidades, torna-se clara a necessidade de equipar as forças policiais com tecnologias de observação e monitoramento inteligentes, capazes de identificar e monitorar indivíduos potencialmente perigosos que possam estar infiltrados nas multidões. Ao mesmo tempo, com sua recente popularização, veículos aéreos não tripulados, também chamados VANTs e conhecidos popularmente como "drones", acabaram por tornar-se ferramentas baratas e eficientes para diversas aplicações, incluindo observação, fornecendo a seus utilizadores a capacidade de monitorar alvos, áreas, ou prédios de forma segura e quase imperceptível. Unindo estas duas tendências, este trabalho apresenta o desenvolvimento de um sistema multi-VANT para observção de alvos móveis em multidões, demonstrando a possibilidade de utilização de pequenos VANTs comerciais comuns para o monitoramento de grupos de pedestres. O principal objetivo de tal sistema é monitorar continuamente indivíduos de interesse em um grupo de pessoas, visitando cada um destes indivíduos alternadamente, de forma a manter um registro geral do estado de cada um deles Um sistema deste tipo poderia, por exemplo, ser utilizado por autoridades no controle de manifestações e outras atividades em que grandes grupos de pessoas estejam envolvidos, ajudando a polícia e outros órgãos a identificar indivíduos com comportamento suspeito ou agressivo mais rapidamente, evitando ou minimizando os efeitos de atitudes de vandalismo e de ataques terroristas. Com o intuíto de abordar tal problema da forma mais completa e adequada possível, esta tese apresenta a concepção e o desenvolvimento de um sistema híbrido composto de três diferentes algoritmos: um algoritmo de distribuição de alvos; um de roteamento; e um de repasse de alvos. Primeiramente, neste sistema, um algoritmo de distribuição de alvos baseado em um paradigma de mercado que simula um leilão distribui os alvos entre os VANTs da melhor forma possível. Os VANTs, por sua vez, utilizam um algoritmo genético de roteamento para resolver uma instância do Problema do Caixeiro Viajante e decidir a melhor rota para visitar cada alvo sob sua responsabilidade. Ao mesmo tempo, o sistema analisa a necessidade de redistribuição dos alvos, ativando um algoritmo capaz de realizar esta ação ao perceber sua necessidade quando na iminência de perder algum alvo de vista. Ao fim de seu desenvolvimento, o sistema proposto foi testado em uma série de experimentos especialmente desenvolvidos para avaliar seu desempenho em situações controladas e comprovar sua eficiência para realizar a missão pretendida. Observing the current scenario, where terrorism and vandalism acts have become commonplace, particularly in big cities, it becomes clear the need to equip law enforcement forces with an efficient observation method, capable of identifying and observing potentially threatening individuals on crowds, to avoid or minimize damage in case of attacks. Moreover, with the popularization of small lightweight Unmanned Aerial Vehicles (UAVs), these have become an affordable and efficient tool, which can be used to track and follow targets or survey areas or buildings quietly, safely and almost undetectably. This work presents the development of a multi-UAV based crowd monitoring system, demonstrating a system that uses small Commercial Of The Shelf (COTS) UAVs to periodically monitor a group of moving walking individuals. The goal of this work is to develop a coordination system for a swarm of UAVS capable of continuously monitoring a large group of individuals (targets) in a crowd, alternately observing each of them at a time while trying to not lose sight of any of these targets. A system equipped with a group of UAVs running this proposal can be used for law-enforcement applications, assisting authorities to monitor crowds in order to identify and to follow suspicious individuals that can have attitudes that could be classified as vandalism or linked to terrorist attack attempts To address this problem a system composed of three parts is proposed and was developed in this thesis. First, an auction algorithm was put in place to distribute interest targets among the multiple UAVs. The UAVs, in turn, make use of a genetic algorithm to calculate the order in which they would visit each of the targets on their observation queue. Moreover, a target handover algorithm was also implemented to redistribute targets among the UAVs in case the system judged that a target was about to be lost by its current observer UAV. The proposed system was evaluated through a set of experiments set-up to verify and to demonstrate the system capabilities to perform such monitoring task, proving its efficiency. During these experiments, it is made clear that the system as a whole has a great potential to solve this kind of moving target monitoring problem that can be mapped to a Time Dependent Travel Salesman Problem (TDTSP), observing targets, and redistributing them among UAVs as necessary during the mission.

International audience; The cops-and-robber (CR) game has been used in mobile robotics as a discretized model (played on a graph G) of pursuit/evasion problems. The "classic" CR version is a perfect information game: the cops' (pursuer's) location is always known to the robber (evader) and vice versa. Many variants of the classic game can be defined: the robber can be invisible and also the robber can be either adversarial (tries to avoid capture) or drunk (performs a random walk). Furthermore, the cops and robber can reside in either nodes or edges of G. Several of these variants are relevant as models or robotic pursuit / evasion. In this paper, we first define carefully several of the variants mentioned above and related quantities such as the cop number and the capture time. Then we introduce and study the cost of visibility (COV), a quantitative measure of the increase in difficulty (from the cops' point of view) when the robber is invisible. In addition to our theoretical results, we present algorithms which can be used to compute capture times and COV of graphs which are analytically intractable. Finally, we present the results of applying these algorithms to the numerical computation of COV.

Multi-robot cells for spot welding use coordinated robots to assemble metal panels via spot welding by coordinated robots, for instance in the construction of car doors. The design of multi-robot cells for spot welding required both cell design and off-line motion planning. Cell design involves resource selection (such as robots and welding guns) and resource configuration, while considering cell productivity, costs, flexibility and reconfigurability. Motion planning involves allocating welding points to each resource and calculating collision-free motion plan for each robot. Currently, cell design and motion planning are sequential and manual activities, managed by different and separate industrial functional units. This results in several cycles before the design converges to a feasible final solution. The proposed approach introduces a unified methodology, aiming at optimizing the holistic cell design and motion planning, that reduces design time and errors. The feasibility of the proposed approach has been demonstrated in several ad-hoc basic replicable cases and in one industrial case. The outcome of this research improves state of the art, reducing design and motion planning time over current technology. Moreover, the method has been integrated into a computerized approach which has the potential to accelerate the whole cell design and motion planning processes and to reduce human efforts. Design and motion planning of multi-robot cells for body-in-white assembly.Method to reduce human effort in the computation of alternative solutions.Simultaneous resolution and optimization of the design and the motion planning.Testing of the approach on several replicable cases and one industrial case.

Home environments are changing as more technological devices are used to improve daily life. The growing demand for high technology in our homes means that robot integration will soon arrive. Home devices are evolving in a connected paradigm in which data flows to perform efficient home task management. Heterogeneous home robots connected in a network can establish a workflow that complements their capabilities and so increases performance within a mission execution. This work addresses the definition and requirements of a robot-group mission in the home context. The proposed solution relies on a network of smart resources, which are defined as cyber-physical systems that provide high-level service execution. Firstly, control middleware architecture is introduced as the execution base for the Smart resources. Next, the Smart resource topology and its integration within a robotic platform are addressed. Services supplied by Smart resources manage their execution through a robot behavior architecture. Robot behavior execution is hierarchically organized through a mission definition that can be established as an individual or collective approach. Environment model and interaction tasks characterize the operation capabilities of each robot within a mission. Mission goal achievement in a heterogeneous group is enhanced through the complement of the interaction capabilities of each robot. To offer a clearer explanation, a full use case is presented in which two robots cooperate to execute a mission and the previously detailed steps are evaluated. Finally, some of the obtained results are discussed as conclusions and future works is introduced., Los entornos domésticos se encuentran sometidos a un proceso de cambio gracias al empleo de dispositivos tecnológicos que mejoran la calidad de vida de las personas. La creciente demanda de alta tecnología en los hogares señala una próxima incorporación de la robótica de servicio. Los dispositivos domésticos están evolucionando hacia un paradigma de conexión en el cual la información fluye para ofrecer una gestión más eficiente. En este entorno, robots heterogéneos conectados a la red pueden establecer un flujo de trabajo que ofreciendo nuevas soluciones y incrementando la eficiencia en la ejecución de tareas. Este trabajo aborda la definición y los requisitos necesarios para la ejecución de misiones en grupos de robots heterogéneos en entornos domésticos. La solución propuesta se apoya en una red de Smart resources, que son definidos como sistemas ciber-físicos que proporcionan servicios de alto nivel. En primer lugar, se presenta la arquitectura del middleware de control en la cual se basa la ejecución de los Smart resources. A continuación se detalla la topología de los Smart resources, así como su integración en plataformas robóticas. Los servicios proporcionados por los Smart resources gestionan su ejecución mediante una arquitectura de comportamientos para robots. La ejecución de estos comportamientos se organiza de forma jerárquica mediante la definición de una misión con un objetivo establecido de forma individual o colectiva a un grupo de robots. Dentro de una misión, las tareas de modelado e interacción con el entorno define las capacidades de operación de los robots dentro de una misión. Mediante la integración de un grupo heterogéneo de robots sus diversas capacidades son complementadas para el logro un objetivo común. A fin de caracterizar esta propuesta, los mecanismos presentados en este documento se evaluarán en detalle a lo largo de una serie experimentos en los cuales un grupo de robots heterogéneos ejecutan una misión colaborativa para alcanzar un objetivo común. Finalmente, los resultados serán discutidos a modo de conclusiones dando lugar el establecimiento de un trabajo futuro., Els entorns domèstics es troben sotmesos a un procés de canvi gràcies a l'ocupació de dispositius tecnològics que milloren la qualitat de vida de les persones. La creixent demanda d'alta tecnologia a les llars assenyala una propera incorporació de la robòtica de servei. Els dispositius domèstics estan evolucionant cap a un paradigma de connexió en el qual la informació flueix per oferir una gestió més eficient. En aquest entorn, robots heterogenis connectats a la xarxa poden establir un flux de treball que ofereix noves solucions i incrementant l'eficiència en l'execució de tasques. Aquest treball aborda la definició i els requisits necessaris per a l'execució de missions en grups de robots heterogenis en entorns domèstics. La solució proposada es recolza en una xarxa de Smart resources, que són definits com a sistemes ciber-físics que proporcionen serveis d'alt nivell. En primer lloc, es presenta l'arquitectura del middleware de control en la qual es basa l'execució dels Smart resources. A continuació es detalla la tipologia dels Smart resources, així com la seva integració en plataformes robòtiques. Els serveis proporcionats pels Smart resources gestionen la seva execució mitjançant una arquitectura de comportaments per a robots. L'execució d'aquests comportaments s'organitza de forma jeràrquica mitjançant la definició d'una missió amb un objectiu establert de forma individual o col·lectiva a un grup de robots. Dins d'una missió, les tasques de modelatge i interacció amb l'entorn defineix les capacitats d'operació dels robots dins d'una missió. Mitjançant la integració d'un grup heterogeni de robots seves diverses capacitats són complementades per a l'assoliment un objectiu comú. Per tal de caracteritzar aquesta proposta, els mecanismes presentats en aquest document s'avaluaran en detall mitjançant d'una sèrie experiments en els quals un grup de robots heterogenis executen una missió col·laborativa per aconseguir un objectiu comú. Finalment, els resultats seran discutits a manera de conclusions donant lloc a l'establiment d'un treball futur., Munera Sánchez, E. (2017). MISSION-ORIENTED HETEROGENEOUS ROBOT COOPERATION BASED ON SMART RESOURCES EXECUTION [Tesis doctoral no publicada]. Universitat Politècnica de València. doi:10.4995/Thesis/10251/88404., TESIS

Includes bibliography (p. 119-126). Number of sources in the bibliography: 114 Thesis (Ph. D.) -- University of Cyprus, Faculty of Engineering, Department of Electrical and Computer Engineering, 2016. The University of Cyprus Library holds the printed form of the thesis. Τα κινούμενα ρομπότ, ως η μετέπειτα γενεά των βιομηχανικών ρομπότ που έχουν εκμοντερνίσει την βιομηχανία, έχουν εισαγάγει τεράστιες ευκαιρίες τεχνολογικής ανάπτυξης στον σύγχρονο κόσμο. Με εφαρμογές που εκτείνονται από το απλό νοικοκυριό μέχρι και στην εξερεύνηση του διαστήματος, νέες καινούργιες εφαρμογές έχουν εισαχθεί. Αυτές οι εφαρμογές χρειάζονται αυξημένη ρομποτική αυτονομία, λόγω της αδυναμίας των χειριστών να είναι παρόντες ή απλά λόγω της ανάγκης για βελτιωμένη απόδοση. Όταν τα ρομπότ λειτουργούν πλέον αυτόνομα, ο συντονισμός μεταξύ τους είναι απαραίτητος ώστε να διασφαλιστεί αποδοτική λειτουργία καθώς επίσης και η αύξηση της παραγωγικότητας. Στις περιπτώσεις απρόσμενων γεγονότων, για παράδειγμα όταν ένα από τα ρομπότ δεν ανταποκρίνεται, τα εναπομείναντα ρομπότ πρέπει να είναι ικανά να συντονιστούν κάτω από νέες συνθήκες έτσι ώστε να πετύχουν τους στόχους τους. Τα σφάλματα κινητήρων είναι ακόμα μια πρόκληση που παρουσιάζεται όταν τα ρομπότ λειτουργούν αυτόνομα, για τον λόγο ότι προκαλούν μειωμένη παραγωγικότητα και δημιουργούν θέματα ασφαλείας. Τα σφάλματα κινητήρων επηρεάζουν την ομαλή λειτουργία των ρομπότ και προκαλούν αλλαγή στην πορεία τους, δημιουργώντας συγκρούσεις, ζημίες και ενδεχόμενους τραυματισμούς Στης διατριβή αυτή προσεγγίζονται οι δυσκολίες συντονισμού μεταξύ των ρομπότ και στον εντοπισμό σφαλμάτων στους κινητήρες για συγκεκριμένα ρομποτικά συστήματα. Πρώτα, παρουσιάζεται μια μέθοδος βελτιστοποίησης του συντονισμού μια ομάδας ρομπότ που λειτουργούν σε μια αποθήκη. Προτείνεται ένας αποδοτικός αλγόριθμος ώστε να εξευρεθεί λύση στο πρόβλημα της βελτιστοποίησης του συντονισμού σε πραγματικό χρόνο. Δεύτερο, χρησιμοποιείται μία μέθοδος ανίχνευσης σφαλμάτων η οποία χρησιμοποιεί οδομετρία για να ανιχνεύσει σφάλμα κινητήρων και τα ταυτοποιεί σε σχέση με τρεις αντίστοιχους τύπους σφαλμάτων. Τρίτο, παρουσιάζεται μια νέα μέθοδος η οποία αυξάνει την ευαισθησία εντοπισμού σφάλματος, ενσωματώνοντας πολλαπλά όρια. Εισάγεται η έννοια του προειδοποιητικού σήματος, του οποίου η συμπεριφορά στον χρόνο χρησιμοποιείται για να ανιχνεύσει σφάλματα μικρής έντασης. Τέταρτο, παρουσιάζουμε μια μονάδα επεξεργασίας η οποία μπορεί να εγκατασταθεί σε ένα κινούμενο ρομότ και να παρέχει διόρθωση πορείας σε περίπτωση ενδεχόμενου σφάλματος, χρησιμοποιώντας ανίχνευση σφάλματος, εντοπισμό και ταυτοποίηση. Η αποδοτικότητα των μεθόδων που προτείνονται αποδεικνύεται δια μέσω προσομοίωσης και επικυρώνεται με τη χρήση σε πραγματικό ρομπότ, με τη χρήση της πειραματικής πλατφόρμας που αναπτύχθηκε και παρουσιάζεται σε αυτή την διατριβή. Mobile robots, as a natural successor of manipulators that revolutionized the industrial world, have introduced vast possibilities for technological advancements in today’s modern era. With applications spanning from simple household cleaning to planetary exploration, new challenging and unpredictable environments are introduced. These applications demand for increased robot autonomy, either due to the inability for human operators to be present or simply due to the need for improved efficiency. When robots operate autonomously, coordination among them is essential to ensure efficient operation and increase productivity. In cases of unexpected events, for example when one of the robots becomes unresponsive, the remaining robots must be able to coordinate under the new conditions and achieve their tasks. Actuator faults is another challenge introduced when robots operate autonomously, causing reduced productivity, as well as raising safety issues. An actuator fault affects the normal operation, causing the robot to drift away from its path with the risk of colliding with an obstacle, causing damages to its surroundings and possibly injuring people. This thesis addresses the challenges of coordination and actuator fault detection for certain mobile robot systems. First, a method is presented for optimizing the coordination of a team of robots operating in a warehouse. An efficient algorithm is proposed to provide the solution of the coordination optimization problem in real-time. Second, a model-based fault detection approach is used that utilizes odometry to detect actuator faults and identifies them with respect to three possible fault-types. Third, a new detection method is presented for increasing detection sensitivity by incorporating multiple thresholds. The concept of warning signal is introduced, whose temporal behavior is used to detect faults of small magnitude. Fourth, we present a module that can be installed on a mobile robot and provide path correction in the event of a fault, using fault detection, isolation and identification. The effectiveness of the proposed methods is demonstrated through simulations and validated on a real mobile robot, using the experimentation platform developed and presented in the thesis.

In the last decade, the development of multi robot systems has shown with growing evidence how a well-balanced deliberative-reactive coordination can provide a group of robots with an efficient and robust collective behavior. In this paper, we want to cover exhaustively this issue from the point of view of the single agent in the general model we have already presented as “roboticle framework”. Starting from a pure mechanical interpretation of an autonomous robot motion we shall understand the notions of stigmergy and affordance by maintaining at the sub-symbolic level all the relevant information useful to drive properly the robot while it participates to the collective action. Specifically, we shall focus on some interesting parameters through which the designer of the single robot governor’s unit could be helped to trigger its individual behavior within a collective scenario.

International audience; In a recent French robotic contest, the objective was to develop a multi-robot system able to autonomously map and explore an unknown area while also detecting and localizing objects in the environment. The scientific issues of this project deal with SLAM (Simultaneous Localization and Mapping), object recognition and multi-robot collaboration for the exploration. As a participant in this challenge, we proposed a new decentralized Markov decision process (Dec-MDP) resolution based on distributed value functions (DVF) to compute multi-robot exploration strategies. The idea is to take advantage of sparse interactions by allowing each robot to calculate locally a strategy that maximizes the explored space while minimizing robots interactions. In this paper, we will present an adaptation of this method to improve also object recognition. It consists in integrating in the DVF the interest to cover explored areas with photos. Robots will then act to maximize the explored space and the photo coverage ensuring a better perception and object recognition. After a brief description of the robotic contest and our system, we will present our Dec-MDP resolution based on DVF and its application to multi-robot exploration. The next part of the paper will be dedicated to the use of DVF to explore and perceive with experimental results from simulated scenarios.

Self-replicating robots represent a new area for prospective advancement in robotics. A self-replicating robot can identify when additional robots are needed to solve a problem or meet user needs, and create them in response to this identified need. This allows robotic systems to respond to changing (or non-predicted) mission needs. Being able to modify the physical system component provides an additional tool for optimizing robotic system performance. This paper begins the process of developing a command and coordination system that makes decisions with the consideration of replication, repair, and retooling capabilities. A high-level algorithm is proposed and qualitatively assessed.

We consider the problem of coordinating a collection of robots at an intersection area taking into account dynamical constraints due to actuator limitations. We adopt the coordination space approach, which is standard in multiple robot motion planning. Assuming the priorities between robots are assigned in advance and the existence of a collision-free trajectory respecting those priorities, we propose a provably safe trajectory planner satisfying kinodynamic constraints. The algorithm is shown to run in real time and to return safe (collision-free) trajectories. Simulation results on synthetic data illustrate the benefits of the approach., Comment: to be presented at ECC2014; 6 pages

In the last decade the development of multirobot systems has come to maturation providing a lot of important results in many applicative domains. Many paradigms and approaches have been devised to this aim but one of them seems very promising for future applications: dense colony of robots where the large numbers of individuals is combined with a very small dimension for each of them. Here, the key point is a behavior-based paradigm embedded in the mobiligence framework as it appears particularly suitable to deal with the sensing activity where the physics of the interaction is made explicit to take advantage from it. Within this point of view the paper explores a design method to deal with sensor information which, avoiding any symbolic representation, is maintained at a somewhat physical level as a metaphor of the events observed in the environment. The idea of substratum is introduced as a convenient representation of the physical level currently in use. The key properties of the thermal metaphor are considered and implemented to trigger appropriately a colony of robots to execute a collective task. The temperature distribution, heat flux, diffusivity and dispersion are all discussed as different aspects of the stigmergy included as a key feature of the swarm which forces each individual to behave collectively.

In this paper, we propose an algorithm for coordinating a group of mobile robots that go through predefined paths in a dynamic industrial environment. Coordination diagrams are used for representing the possible collisions among the vehicles. We exploit this information for developing a centralised and incremental planning algorithm that allows to coordinate the vehicles and to take into account unexpected events that can occur in an industrial environment. Simulation tests have been executed in order to compare the performance of our algorithm with the one currently implemented by the company.

As product life cycle becomes less and less every day, having flexible manufacturing processes for any companies seems more demanding. In the assembling of closures, i.e. opening parts in car body, hemming process is the one which needs more attention. This paper focused on the robot roller hemming process and how to reduce its cycle time by introducing a fast roller hemming process. A robot roller hemming process of a tailgate of Saab 93 SportCombi model is investigated as a case study in this paper. By applying task separation, robot coordination, and robot cell configuration principles in the roller hemming process, three alternatives are proposed, developed, and remarkable reduction in cycle times achieved [1]., {"references":["Babak Saboori, Behzad Saboori, \"Development of roller hemming\nprocess in automotive industry - Saab Automobile AB,\" M.S. thesis,\nDept. Product and Production Development, Chalmers University of\nTechnology, Gothenburg, Sweden, 2009.","B. Jonkers, \"Voestalpine Polynorm Automotive,\" M.S. thesis,\nUniversiteit Twente, Bunschoten, Netherlands, 2006.","Andreas Engdahl, \"En j├ñmförande studie av rullfalsning kontra\nkonventionell falsning,\" B.S. thesis, Dept. Mechanical Eng., Chalmers\nUniversity of Technology, Gothenburg, Sweden, 2006.","Mats Sigvant, \"The hemming process, a numerical and experimental\nstudy,\" Dept. Mechanical Eng., Chalmers University of Technology,\nGothenburg, Sweden, 2003.","Allan Tubaileh, Ibrahim Hammad, and Loay Al Kafafi, \"Robot Cell\nPlanning,\" In Proc. the 2007 WASET, vol. 20 pp. 250-255, 2007.","R. Bohlin, L. E. Kavraki, \"Path Planning Using Lazy PRM,\" In Proc. the\n2000 IEEE International Conference on Robotics & Automation San\nFrancisco, 2000.","\"Automatic Path Planning crash course,\" Fraunhofer-Chalmers research\nCentre, Gothenburg, Sweden, 2009.","V. MATA and A. TUBAILEH, \"The machine layout problem in robot\ncells,\" INT. J. PROD. RES., vol. 36, no. 5, pp. 1273-1292, 1998.","Marcus Andersson, \"Effektiv simulering och analys av flexibla\nslangkomponenter,\" M.S. thesis, Dept. Product and Production\nDevelopment, Chalmers University of Technology, Gothenburg,\nSweden, 2008.\n[10] VINNOVA, the Swedish Govermental Agency for Innovation Systems\n2007, MORE Program Projects Catalog, \"Simulation and path planning\nfor Flexible Materials,\" ISSN: 1650-3120, Sweden, 2007.\n[11] Johan S. Carlson, Rikard Söderberg, Robert Bohlin, Lars Lindkvist, and\nTomas Hermansson, \"Non-nominal path planning of assembly\nprocesses,\" In Proc. the 2005 ASME International Mechanical\nEngineering Congress and exposition November 5-11, Orlando, FL,\n2005.\n[12] Johan Segeborn, Johan S. Carlson, Robert Bohlin, and Rikard\nSöderberg, \"Geometry Design Supported by Minimizing and Visualizing\nCollision in Dynamic Packing,\" In Proc. the 2007 WASET, vol. 25 pp.\n164-171, 2007.\n[13] Dandan Zhang, Liwei Qi, \"Virtual engineering II, Optimal cell layout for\nindustrial robots improves manufacturing productivity,\" Special report\ndancing with the dragon, ABB review, pp. 90-92, China, 2008."]}

A Lyndon word is a non-empty word strictly smaller in the lexicographic order than any of its suffixes, except itself and the empty word. In this paper, we show how Lyndon words can be used in the distributed control of a set of n weak mobile robots. By weak, we mean that the robots are anonymous, memoryless, without any common sense of direction, and unable to communicate in an other way than observation. An efficient and simple deterministic protocol to form a regular n-gon is presented and proven for n prime., 13 pages

In this paper, we propose a compliant motion control strategy for handling a single object by two similar industrial robots. The dynamics of the object carried by the two robots is assimilated to the dynamics of a mass-spring-damper system described by a piecewise linear model (PWA). The coordination of the two robots is accomplished using a master slave synchronization approach dedicated for PWA systems, based on the Lyapunov theory, and solved via Linear Matrix Inequalities (LMIs). The performances of the proposed approach are proved by simulation results and compared to a related approach., Comment: 7 pages, 6 Figures