En ce qui concerne la hiérarchie de contrôle des micro-réseaux, la coordination des contrôleurs locaux est obligatoire aux niveaux secondaire et tertiaire. Au lieu d'utiliser une unité centrale comme approche conventionnelle, dans ce travail, des schémas distribués sont considérés. Les approches distribuées ont récemment fait l'objet d'une attention particulière en raison de leurs avantages en termes de fiabilité, d'évolutivité et de sécurité. Le système multi-agents est une technique avancée dont les propriétés les rendent aptes à servir de base à la construction de systèmes de contrôle distribués modernes. La thèse porte sur la conception d'agents visant à distribuer des algorithmes de contrôle et d'optimisation dans des micro-réseaux avec un déploiement en ligne réaliste sur une plate-forme Hardware-in-the-Loop. Sur la base de l'architecture à trois couches fournie par micro-réseaux, une plate-forme de laboratoire avec configuration Hardware-in-the-Loop est construite au niveau du système. Cette plateforme comprend deux parties : (1) un simulateur numérique en temps réel permet de simuler en temps réel des micro-réseaux de cas de test avec des contrôleurs locaux ; et (2) un cluster de Raspberry PI représente le système multi-agent fonctionnant dans un réseau de communication physique épars. Un agent est un programme en Python exécuté sur un seul Raspberry PI qui permet de transférer des données à ses voisins et d’effectuer des calculs selon des algorithmes de manière distribuée.Dans la thèse, nous appliquons les algorithmes distribués pour les niveaux de contrôle secondaire et tertiaire. Les contrôles secondaires distribués dans un micro-réseau îloté sont présentés selon deux approches d'algorithme de consensus à temps fini et d'algorithme de consensus moyen avec les améliorations des performances. Une extension de la plate-forme avec la Power Hardware-in-the-Loop et la communication basée sur la norme IEC 61850 est traitée pour rapprocher le déploiement des agents des applications industrielles. Au niveau de contrôle supérieur, les agents exécutent la méthode des multiplicateurs à sens alternatif pour déterminer les points de fonctionnement optimaux des systèmes de micro-réseaux en état d'îlot et de connexion au réseau. Les objectifs de contrôle secondaire et tertiaire sont atteints dans un cadre unique qui est rarement mentionné dans d'autres études.Dans l'ensemble, l'agent est explicitement étudié et déployé dans des conditions réalistes pour faciliter l'application des algorithmes distribués pour le contrôle hiérarchique dans les micro-réseaux. Cette recherche constitue une étape supplémentaire qui rapproche les algorithmes distribués de l'implémentation sur site. / In terms of the control hierarchy of microgrids, the coordination of local controllers is mandatory in the secondary and tertiary levels. Instead of using a central unit as conventional approaches, in this work, distributed schemes are considered. The distributed approaches have been taken attention widely recently due to the advantages of reliability, scalability, and security. The multi-agent system is an advanced technique having properties that make them suitable for acting as a basis for building modern distributed control systems. The thesis focuses on the design of agents aiming to distributed control and optimization algorithms in microgrids with realistic on-line deployment on a Hardware-in-the-loop platform. Based on the provided three-layer architecture of microgrids, a laboratory platform with Hardware-in-the-loop setup is constructed in the system level. This platform includes two parts: (1) a digital real-time simulator uses to simulate test case microgrids with local controllers in real-time; and (2) a cluster of hardware Raspberry PIs represents the multi-agent system operating in a sparse physical communication network. An agent is a Python-based program run on a single Raspberry PI owing abilities to transfer data with neighbors and computing algorithms to control the microgrid in a distributed manner.In the thesis, we apply the distributed algorithms for both secondary and tertiary control level. The distributed secondary controls in an islanded microgrid are presented in two approaches of finite-time consensus algorithm and average consensus algorithm with the improvements in performances. An extension of the platform with Power Hardware-in-the-Loop and IEC 61850-based communication is processed to make the deployment of agents closer to industrial applications. On the top control level, the agents execute the Alternating Direction Method of Multipliers to find out the optimal operation points of microgrid systems in both islanded and grid-connect state. The secondary and tertiary control objectives are achieved in a single framework which is rarely reported in other studies.Overall, the agent is explicitly investigated and deployed in the realistic conditions to facilitate applications of the distributed algorithms for the hierarchical control in microgrids. This research gives a further step making the distributed algorithms closer to onsite implementation.

This thesis proposes a distributed robust control approach for low-thrust nanosatellite formation flying. The presented control approach is the further development of an already existing approach which combines robust control and distributed control using the consensus approach. The adjustments presented in this thesis are intended to enable the usage of the control approach in nanosatellite missions such as the upcoming NetSat mission. Stability criteria, optimization goals and constraints such as the limited maximum thrust are formulated with the help of Linear Matrix Inequalities (LMIs). In addition, the presented control approach includes methods for exploiting the maximum thrust and for collision avoidance. Due to the design as a distributed controller based on the consensus approach, a satellite formation can be maintained even in the case of the failure of the propulsion system and/or Attitude Determination and Control System (ADCS) of a single satellite. To verify the design of the control approach, simulations of the formation scenarios planned for the NetSat mission are performed with a satellite formation simulation framework based on Orekit and MATLAB®.

Intelligent transport systems are preparing to welcome connected and automated vehicles (CAVs), although it is uncertain which algorithms should be employed for the effective and efficient management of CAV systems. Even though remarkable improvements in telecommunication technologies, such as vehicle-to-everything (V2X), enable communication and computation sharing among different agents, e.g. vehicles and infrastructures, within existing approaches, a significant part of the computation burden is still typically assigned to central units. Distributed algorithms, on the other hand, could alleviate traffic units from most, if not all, of the high dimensional calculation duties, while improving security and remaining effective. In this paper, we propose a formation-control-inspired distributed algorithm to rearrange vehicles’ passing time periods through an intersection and a novel formulation of the underlying trajectory optimization problem so that vehicles need to exchange and process only a limited amount of information. We include early simulation results to demonstrate the effectiveness of our approach.

Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: RoboCup promotes research in robotics and multi-robot systems (MRS). The RoboCup Small Size League (SSL), in particular, offers an entry level opportunity to take part in this field of study. This thesis presents a starting phase for research in robotics and MRS at Stellenbosch University. It includes the full documentation of the mechanical, electronic and software design of an omni-directional soccer robot for RoboCup SSL. The robot is also meant to operate as a hardware and software development platform for research in MRS. The platform was therefore designed with high-level programming language compatibility, a wide range of connectivity, and modularity in mind. The robot uses a single board computer (SBC) running a Linux operating system to accomplish these objectives. Moreover, a driver class library was written in C++ as a software application interface (API) for future development on the robot platform. The robot was also developed with a particular focus on a distributed control architecture. "Player" was implemented as the middleware, which can be used for communication between multiple robots in a distributed environment. Additionally, three tests were performed to demonstrate the functionality of the prototype: a PI speed control test, a direction accuracy test and a static communication test using the middleware. Recommendations for possible future work are also given. / AFRIKAANSE OPSOMMING: RoboCup bevorder navorsing in robotika en multi-robot-stelsels (MRS). Die RoboCup Klein Liga (KL) bied in die besonder die geleentheid om op intreevlak navorsing te doen in hierdie veld. Hierdie tesis verteenwoordig die eerste fase van navorsing in robotika en MRS by Stellenbosch Universiteit. Dit sluit die volledige dokumentasie van die meganiese, elektroniese en sagteware-ontwerp van ’n omnidireksionele sokker-robot vir die KL in. Die robot is ook veronderstel om te dien as ’n hardeware- en sagteware-ontwikkelingsplatform vir navorsing in MRS. Die platform is dus ontwerp met ’n verskeidenheid van uitbreingsmoontlikhede en modulariteit in gedagte asook die moontlikheid om gebruik te maak van ’n hoë-vlak programmeertaal. Om hierdie doelwitte te bereik, maak die robot gebruik van ’n enkel-bord-rekenaar met ’n Linux bedryfstelsel. Verder was ’n sagteware drywer in C++ geskryf om te dien as ’n sagteware-koppelvlak vir toekomstige ontwikkeling op die robot platform. Die robot is ook ontwikkel met die besondere fokus op ’n gedesentraliseerde beheerstels. Player was geïmplementeer as die middelware, wat gebruik kan word vir kommunikasie tussen verskeie robotte in ’n gedesentralliseerde beheerstelsel. Daar is drie toetse uitgevoer om die funksionaliteit van die prototipe te demonstreer, ’n PI spoed beheer toets, ’n rigting akkuraatheidstoets en ’n statiese kommunikasie toets deur van die middelware gebruik te maak. Aanbevelings vir moontlike toekomstige werk word ook verskaf.

An industrial control valve has been designed by Eaton (AxisPro® valve). The servo performance valve has onboard electronics that features external and internal sensor interfaces, advanced control modes and network capability. Advanced control modes are implement in the valves firmware. With the help of the white space it is possilbe to execute custom code directly on the valve that interact with these controls. Small OEM applications, like rubber moulding machines, benefit from the comination of build in controls and custom code, to provide adaptations for their special machines.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This thesis describes the development of a distributed control system for SSL soccer robots. The project continues on work done to develop a robotics research platform at Stellenbosch University. The wireless communication system is implemented using Player middleware. This enables high level programming of the robot drivers and communication clients, resulting in an easily modifiable system. The system is developed to be used as either a centralised or decentralised control system. The software of the robot’s motor controller unit is updated to ensure optimal movement. Slippage of the robot’s wheels restricts the robot’s movement capabilities. Trajectory tracking software is developed to ensure that the robot follows the desired trajectory while operating within its physical limits. The distributed control architecture reduces the robots dependency on the wireless network and the off-field computer. The robots are given some autonomy by integrating the navigation and control on the robot self. Kalman filters are designed to estimate the robots translational and rotational velocities. The Kalman filters fuse vision data from an overhead vision system with inertial measurements of an on-board IMU. This ensures reliable and accurate position, orientation and velocity information on the robot. Test results show an improvement in the controller performance as a result of the proposed system. / AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die ontwikkeling van ’n verspreidebeheerstelsel vir SSL sokker robotte. Die projek gaan voort op vorige werk wat gedoen is om ’n robotika navorsingsplatform aan die Universiteit van Stellenbosch te ontwikkel. Die kommunikasiestelsel is geïmplementeer met behulp van Player middelware. Dit stel die robotbeheerders en kommunikasiekliënte in staat om in hoë vlak tale geprogrameer te word. Dit lei tot ’n maklik veranderbare stelsel. Die stelsel is so ontwikkel dat dit gebruik kan word as óf ’n gesentraliseerde of verspreidebeheerstelsel. Die sagteware van die motorbeheer eenheid is opgedateer om optimale robot beweging te verseker. As die robot se wiele gly beperk dit die robot se bewegingsvermoëns. Trajekvolgings sagteware is ontwikkel om te verseker dat die robot die gewenste pad volg, terwyl dit binne sy fisiese operasionele grense bly. Die verspreibeheerargitektuur verminder die robot se afhanklikheid op die kommunikasienetwerk en die sentrale rekenaar. Die robot is ’n mate van outonomie gegee deur die integrasie van die navigasie en beheer op die robot self te doen. Kalman filters is ontwerp om die robot se translasie en rotasie snelhede te beraam. Die Kalman filters kombineer visuele data van ’n oorhoofse visiestelsel met inertia metings van ’n IMU op die robot. Dit verseker betroubare en akkurate posisie, oriëntasie en snelheids inligting. Toetsresultate toon ’n verbetering in die beheervermoë as ’n gevolg van die voorgestelde stelsel.

Current global business competition has resulted in significant challenges for manufacturing and production sectors focused on shorter product lifecyc1es, more diverse and customized products as well as cost pressures from competitors and customers. To remain competitive, manufacturers, particularly in automotive industry, require the next generation of manufacturing paradigms supporting flexible and reconfigurable production systems that allow quick system changeovers for various types of products. In addition, closer integration of shop floor and business systems is required as indicated by the research efforts in investigating "Agile and Collaborative Manufacturing Systems" in supporting the production unit throughout the manufacturing lifecycles. The integration of a business enterprise with its shop-floor and lifecycle supply partners is currently only achieved through complex proprietary solutions due to differences in technology, particularly between automation and business systems. The situation is further complicated by the diverse types of automation control devices employed. Recently, the emerging technology of Service Oriented Architecture's (SOA's) and Web Services (WS) has been demonstrated and proved successful in linking business applications. The adoption of this Web Services approach at the automation level, that would enable a seamless integration of business enterprise and a shop-floor system, is an active research topic within the automotive domain. If successful, reconfigurable automation systems formed by a network of collaborative autonomous and open control platform in distributed, loosely coupled manufacturing environment can be realized through a unifying platform of WS interfaces for devices communication. The adoption of SOA- Web Services on embedded automation devices can be achieved employing Device Profile for Web Services (DPWS) protocols which encapsulate device control functionality as provided services (e.g. device I/O operation, device state notification, device discovery) and business application interfaces into physical control components of machining automation. This novel approach supports the possibility of integrating pervasive enterprise applications through unifying Web Services interfaces and neutral Simple Object Access Protocol (SOAP) message communication between control systems and business applications over standard Ethernet-Local Area Networks (LAN's). In addition, the re-configurability of the automation system is enhanced via the utilisation of Web Services throughout an automated control, build, installation, test, maintenance and reuse system lifecycle via device self-discovery provided by the DPWS protocol.

To develop more competitive solutions, one of the trends in the development of drive systems for electric and hybrid electric vehicles (EVs/HEVs) is to integrate the power electronic converter and the electric motor. This thesis aims to investigate the performance and the operation of modular converters in integrated motor drive systems for EVs/HEVs. In the first part, the concept of integrated modular motor drive systems for EVs/HEVs is introduced. Three suitable modular converter topologies, namely, the stacked polyphase bridges (SPB) converter, the parallel-connected polyphase bridges (PPB) converter and the modular high frequency (MHF) converter, are evaluated and compared with conventional electric drives in terms of power losses, energy storage requirements, and semiconductor costs. In the second part of the thesis, the harmonic content of the dc-link current of the SPB converter is analyzed. By adopting an interleaving modulation the size of the dc-link capacitor can be reduced without increasing the switching frequency, which is beneficial for achieving a compact integrated system. This method allows for around 80% reduction of the dc-link capacitance for vehicle drives, resulting in a significant size reduction of the power converter and improved integration. Finally, a communication-based distributed control system for the SPB converter is presented. The communication delay arising from the serial communication is inevitable, thus a timing analysis is also presented. It has been found that stability is maintained even when the baud rate of the SPI communication is lower than 1 Mbps, indicating that other communication protocols with lower bandwidths can also be adopted for this topology. The analytical investigations provided in this thesis are validated by experiments on a four-submodule laboratory prototype. Experimental results verify the correctness of the theoretical analysis, as well as the dynamic performance of the distributed control system. / <p>QC 20161121</p>

L'objectif de cette thèse s'inscrit dans la cadre général du développement d'une stratégie de contrôle intelligent distribué en robotique collective. En effet, dans un avenir proche, de nombreux robots vont progressivement intégrer notre environnent aussi bien dans les milieux industriel que domestique. L'objectif de ces robots sera de fournir, de manière autonome, des services aux êtres humains afin de leurs faciliter la vie quotidienne comme par exemple dans le cas de robots compagnons. Ces services pourront être le résultat du travail d'un robot ou bien la conséquence de la coopération de plusieurs robots homogènes et/ou hétérogènes regroupés au sein d'un réseau. Dans ce contexte, si les progrès technologiques permettent sans problème de communiquer et d'échanger des données entre deux agents artificiels distants, la conception de stratégies de contrôle permettant l'auto-organisation de plusieurs robots dans le but de réaliser une tâche précise est encore aujourd'hui un verrou scientifique important. Cette thèse a donc pour but de proposer des pistes pour élaborer des stratégies de contrôle intelligent pour des systèmes multi-robots dans le cadre plus particulier de la logistique industrielle. En effet, le domaine de logistique industrielle nécessite l'utilisation de nombreux robots mobiles comme par exemple des AGV (Automatic Guided Vehicles) pour transporter et stoker des marchandises. Dans ce contexte, nous pensons que le domaine de la logistique peut tirer bénéfice de l'utilisation de systèmes multi-robots. Dans un premier temps, cette thèse aborde donc la problématique de transport d'objet volumineux et encombrant par une formation de robot. Effectivement, il semble que la solution qui consiste à utiliser un ensemble de robots identiques pour transporter des charges de grandes envergures soit, d'une part, très intéressante d'un point de vue économique et, d'autre part, plus robuste et flexible d'un point vue technologique. Dans un deuxième temps, cette thèse aborde l'utilisation d'un réseau de robots hétérogènes qui sont capables de s'organiser afin de réaliser une tâche précise dans un milieu dynamique. Les travaux effectués dans le cadre de la présente thèse doctorale ont donc abouti à la proposition des stratégies viables de contrôle intelligent pour des systèmes multi-robots. Une étude d'application des concepts étudiés a été réalisée, implantée et validée dans le cadre plus particulier de la logistique industrielle. Elle a concerné d'abord le contexte d'un groupe multi-robots homogène, puis a été étendue au contexte d'un système multi-robots hétérogènes. Les points forts des travaux réalisés peuvent être résumés comme ceci :- Proposition, conception, réalisation et validation expérimentale d'une stratégie de contrôle adaptatif par l'apprentissage artificiel pour un robot non-holonomique. Quatre publications internationales ont valorisé cette partie des travaux.- Proposition, conception, réalisation et validation expérimentale d'une stratégie de contrôle hybridant la vision artificielle et l'apprentissage artificiel pour un groupe de robots homogènes. Deux publications internationales ont valorisé cette partie des travaux.- Proposition, conception, réalisation et validation expérimentale d'une stratégie de contrôle hybridant la vision artificielle et l'apprentissage artificiel pour un groupe de robots hétérogènes. Deux publications internationales ont valorisé cette partie des travaux. Il est pertinent de souligner que les travaux relatifs aux aspects précités ont été couronnés par le prix : ″Innovation Award 2011″ de Industrial Robot / In this thesis, it concentrated the multi robot team navigating in an unknown environment. In our multi robot team, there is a humanoid robot as a leader and a team of two-wheel nonholonomic robots which form a vertical formation. Besides, a top camera and a computer which is a supervisor are the auxiliary robots in the multi robot team. The main purpose of the thesis is to propose an online and an offline navigation strategy for the closed and open area respectively. The core of navigation strategies is the same and it included path planning part and control part. Both the two parts constructed on the virtual structure of the formation robot team. In the former part, it improved the path planning part by the reinforcement Q learning and the image processing to acknowledge the unknown environment. And it applied the Adaptive Neural Fuzzy Inference System (ANFIS) algorithm to control of both the single nonholonomic robot and formation robot team. Furthermore, the strategies are applied to the formation robot team and the multi robot team in both closed and open environment. Simulations and real experiments are provided in the detail in the thesis. The strong points of the contribution are :- Proposition, conception, realization and experimental validation of machine learning based adaptive control for a nonholonomic single robot (in a group of robots). Four international publications have valorized this part of the doctoral Works. - Proposition, conception, realization and experimental validation of an adaptive intelligent control strategy hybridizing Artificial vision and Machine Learning for a group of nonholonomic homogeneous robots. Two international publications have valorized this part of the doctoral Works.- Proposition, conception, realization and experimental validation of an adaptive intelligent control strategy hybridizing Artificial vision and Machine Learning for a group of heterogeneous robots. Two international publications have valorized this part of the doctoral Works. It is pertinent to emphasize the investigations relative to the above-mentioned works have been awarded by: ″Innovation Award 2011″ of Industrial Robot

Este trabalho propõe a análise da comunicação sem fio para um sistema de controle distribuído de semáforos, a partir da revisão das literaturas, realização de simulações e experimentos, os quais consideram as especificações estabelecidas para o sistema de semáforos. As simulações e os experimentos se baseiam na avaliação do comportamento da comunicação perante a alteração de alguns parâmetros de configuração da rede. O estudo apresentado envolve análises relacionadas ao padrão IEEE 802.11g e às definições da camada física apresentadas nas especificações do padrão. Os métodos utilizados envolvem o estudo e experimentação de parâmetros relacionados à potência de transmissão e recepção, além de análise dos esquemas de modulação utilizados pelo padrão IEEE 802.11g. A metodologia aplicada a este trabalho envolve o conhecimento das características e capacidade dos esquemas de modulação responsáveis pela definição das taxas de transmissão. As análises mostram que a possibilidade de adequação dos parâmetros de configuração de rede, levando em consideração o cenário de aplicação, pode ser um fator essencial para o bom desempenho de todo o sistema. / This work proposes the analysis of wireless communication for a distributed control system of traffic lights, from the review of the literature and conducting simulations and experiments, which consider the specifications established for traffic light system. The simulations and experiments are based on the evaluation of the communication behavior towards changing some network configuration parameters. The study presented involves analysis related to the IEEE 802.11g standard and definitions of the physical layer shown in standard specifications. The methods used involve the study and testing of parameters related to power transmission and reception, and analysis of modulation schemes used by the IEEE 802.11g standard. The methodology applied to this work involves the knowledge of the characteristics and capacity of modulation schemes responsible for setting transmission rates. The analyses show that the possibility of adaptation network configuration parameters considering the application scenario may be an essential factor to the performance of the entire system.