M.Ing. / The dissertation covers the establishment of a project from the point of view of a project manager. The document refers to examples where possible to illustrate the actual process through which a project goes during the life-cycle of the project. The first chapter provides an introduction to the context of the project and informs the reader of the type of project which the dissertation discusses. An overview of SCAD A (Supervisory Control and Data Acquisition) systems is discussed followed by field hardware to highlight the environment of typical engineering projects in the automation industry. An introduction to project management is discussed to set the context of the dissertation in motion. The second chapter covers the relevant theoretical stages of a project starting from the early stages of defining the project scope through to the project closure. Each of the stages in the project are dissected and considered within the context of a typical SCAD A oriented project. The third chapter is a case study of the "Jwaneng SCADA Project," which is the name assigned to the project from this point onwards. The project illustrates a typical project which an engineering project manager will manage. The project covers the details of the work involved in the project by passing through all the stages involved in an engineering project. Each stage of the project is illustrated by making reference to appendices containing project specific documents. The project is considered from the point of the original development of the project plan through to the completion of the project. This involves extensive controlling and ensuring that the project is running smoothly. These basic principles are illustrated in the document and aim to inform the reader on the successful dissection and implementation of a proper engineering project plan from start to finish.

With the increasing demand for electrical power and the growing need for the restructuring of the power industry, electric power systems have become highly complex with inherent complicated dynamics. Therefore, the study of power system stability has continued to receive significant attention from both academic researchers and industrial practitioners. This thesis focuses on supervisory wide-area control for rotor angle stability of multi-machine power systems using Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR) control theory with guaranteed robustness. The supervisory controllers are developed in both continuous-time and discrete-time framework and their performances and robustness are assessed using both frequency-domain tools, and time-domain simulation results. The impact of the communication time-delays that commonly exist in wide-area power system control on the performance and robustness of the closed-loop system is investigated. In particular, different methods of incorporating such time-delays into the design of the supervisory LQG controller are considered. This thesis proposes a modified supervisory LQG controller that utilizes the Extended Kalman Filter to estimate the unknown/varying time-delays. Simulation results obtained using numerical examples involving non-linear power system models demonstrate the benefits of the proposed scheme for both time-invariant and time-varying delays. The resulting supervisory control scheme is well suited for maintaining power system stability in the presence of communication time-delays.

The increasing demand for electricity over the last few decades has not been followed by adequate growth in electric infrastructure. As a result, the reliability and safety of the electric grids are facing tremendously growing pressure. Large blackouts in the recent past indicate that sustaining system reliability and integrity turns out to be more and more difficult due to reduced transmission capacity margins and increased stress on the system. Due to the heavy loading conditions that occur when the system is under stress, the protection systems are susceptible to mis-operation. It is under such severe situations that the network cannot afford to lose its critical elements like the main generation units and transmission corridors. In addition to the slow but steady variations in the network structure over a long term, the grid also experiences drastic changes during the occurrence of a disturbance. One of the main reasons why protection relays mis-operate is due to the inability of the relays to adjust to the evolving network scenario. Such failures greatly compound the severity of the disturbance, while diminishing network integrity leading to catastrophic system-wide outages. With the advancement of Wide Area Measurement Systems (WAMS), it is now possible to redesign network protection schemes to make them more adaptive and thus improve the security of the system. Often flagged for exacerbating the events leading to a blackout, the back-up distance protection relay scheme for transmission line protection and the loss-of-field relay scheme for generator unit protection can be greatly improved from an adaptability-oriented redesign. Protection schemes in general would benefit from a power re-distribution technique that helps predict generator outputs immediately after the occurrence of a contingency. / Ph. D.

In decentralized control, agents have only a partial view and partial control of the system and must cooperate to achieve the control objective. In order to synthesize a decentralized control solution, a specification must satisfy the co-observability property. Existing co-observability verification methods require the possibly intractable construction of the complete system. To address this issue, we introduce an incremental verification of co-observability approach. Selected subgroups of the system are evaluated individually, until verification is complete. The new method is potentially much more efficient than the monolithic approaches, in particular for systems composed of many subsystems, allowing for some intractable problems to be manageable. Properties of this new strategy are presented, along with a corresponding algorithm and an example. To further increase the scalability of decentralized control, we wish to adapt the existing Hierarchical Interface-Based Supervisory Control (HISC) to support it. We introduce the Hierarchical Interface-Based Decentralized Supervisory Control (HIDSC) framework that extends HISC to decentralized control. To adapt co-observability for HIDSC, we propose a per-component definition of co-observability along with a verification strategy that requires only a single component at a time in order to verify co-observability. Finally, we provide and prove the necessary and sufficient conditions for supervisory control existence in the HIDSC framework and illustrate our approach with an example. As the entire system model never needs to be constructed, HIDSC potentially provides significant savings. / Thesis / Doctor of Philosophy (PhD)

No description available.

This thesis focuses on the issues related to the implementation of theoretical timed discrete-event systems (TDES) supervisors. In particular, we examine issues related to implementing TDES as sampled-data (SD) controllers, which were introduced by Wang and Leduc. An SD controller is driven by a periodic clock and sees the system as a series of inputs and outputs. On each clock edge (tick event), it samples its inputs, changes state, and updates its outputs. / This thesis focuses on the issues related to the implementation of theoretical timed discrete-event systems (TDES) supervisors. In particular, we examine issues related to implementing TDES as sampled-data (SD) controllers, which were introduced by Wang and Leduc. An SD controller is driven by a periodic clock and sees the system as a series of inputs and outputs. On each clock edge (tick event), it samples its inputs, changes state, and updates its outputs. We first introduce the sampled-data setting from Wang, and then define the sampled-data properties he identified, including the SD controllability property. We then introduce Wang's formal representation of an SD controller as a Moore synchronous finite state machine (FSM). We then discuss Wang's modular and centralized translation method. We next introduced new modular results for the SD controllability point 3.1, SD controllability point 3.2, SD controllability point 4, activity loop free and S-singular prohibitable behaviour that allow one to verify the properties using only a portion of the system, instead of having to construct the entire system model. This should allow faster verification times as well as allow larger systems to be verified. We then introduce for the first time algorithms to verify Wang's CS Deterministic and non self-loop ALF properties. The remainder of the thesis focuses on developing algorithms and software to automatically convert a TDES first into an FSM, and then into a VERILOG module. VERILOG is a hardware description language which allows our FSM to be compiled and implemented on digital logic devices such as an FPGA. We then tested our method by modelling a simple door locking system as TDES, checking that the system satisfies the required sampled-data properties, and then translating the result into VERILOG. The above algorithms and methods have all been implemented as a part of the graphical DES research tool, DESpot. / Thesis / Master of Computer Science (MCS)

<p> Hierarchical Interface-based Supervisory Control (HISC) decomposes a discrete-event system (DES) into a high-level subsystem which communicates with n ≥ 1 low-level subsystems, through separate interfaces which restrict the interaction of the subsystems. It provides a set of local conditions that can be used to verify global conditions such as nonblocking and controllability. As each clause of the definition can be verified using a single subsystem, the complete system model never needs to be stored in memory, offering potentially significant savings in computational resources.</p> <p> Currently, a designer must create the supervisors for a HISC system himself, and then verify that they satisfy the HISC conditions. In this thesis, we develop a synthesis method that respects the HISC hierarchical structure. We replace the supervisor for each level by a corresponding specification DES. We then do a per level synthesis to construct for each level a maximally permissive supervisor that satisfies the corresponding HISC conditions.</p> <p> We define a set of language based fixpoint operators and show that they compute the required level-wise supremal languages. We then present algorithms that implement the fixpoint operators. We present a complexity analysis for the algorithms and show that they potentially offer significant improvement over the monolithic approach.</p> <p> A large manufacturing system example (estimated worst case state space on the order of 10^22) extended from the AIP example is discussed. A software tool for synthesis and verification of HISC systems using our approach was also developed.</p> / Thesis / Master of Applied Science (MASc)

This thesis focuses on issues related to implementing theoretical Discrete-Event Systems (DES) supervisors, and the concurrency and timing delay issues involved. Sampled-data (SD) supervisory control deals with timed DES (TDES) systems where the supervisors will be implemented as SD controllers. An SD controller is driven by a periodic clock and sees the system as a series of inputs and outputs. On each clock edge (tick event), it samples its inputs, changes states, and updates its outputs. In this thesis, we identify a set of existing TDES properties that will be useful to our work, but not sufficient. We extend the TDES controllability definition to a new definition, SD controllability, which captures several new properties that will be useful in dealing with concurrency issues, as well as make it easier to translate a TDES supervisor into an SD controller. We then establish a formal representation of an SD controller as a Moore Finite State Machine (FSM), and describe how to translate a TDES supervisor to a FSM, as well as necessary properties to be able to do so. We discuss how to construct a single centralized controller, as well as a set of modular controllers and show that they will produce equivalent output. Next, we capture the enablement and forcing action of a translated controller in the form of a TDES supervisory control map, and show that the closed-loop behavior of this map and the plant is the same as that of the plant and the original TDES supervisor. We also show that our method is robust with respect to nonblocking and certain variations in the actual behavior of our physical system. We also introduce a set of predicate-based algorithms to verify the SD controllability property, as well as certain other conditions that we require. We have created a software tool for verifying these conditions and provide the source code in the appendix. We have implemented these algorithms using binary decision diagrams (BDD). For illustrative purpose, we have produced a set of examples which fail the key conditions discussed in this thesis, as well as a successful application example based on a Flexible Manufacturing System. We also presented the corresponding FSM, translated from the example's supervisors. / Thesis / Master of Applied Science (MASc)

A system is described for identifying obstacle-free landing sites for a vertical-takeoff-and-landing (VTOL) semi-autonomous unmanned aerial vehicle (UAV) from point cloud data obtained from a stereo vision system. The relatively inexpensive, commercially available Bumblebee stereo vision camera was selected for this study. A "point cloud viewer" computer program was written to analyze point cloud data obtained from 2D images transmitted from the UAV to a remote ground station. The program divides the point cloud data into segments, identifies the best-fit plane through the data for each segment, and performs an independent analysis on each segment to assess the feasibility of landing in that area. The program also rapidly presents the stereo vision information and analysis to the remote mission supervisor who can make quick, reliable decisions about where to safely land the UAV. The features of the program and the methods used to identify suitable landing sites are presented in this thesis. Also presented are the results of a user study that compares the abilities of humans and computer-supported point cloud analysis in certain aspects of landing site assessment. The study demonstrates that the computer-supported evaluation of potential landing sites provides an immense benefit to the UAV supervisor. / Master of Science

Made available in DSpace on 2016-12-12T17:38:32Z (GMT). No. of bitstreams: 1 Yuri k Lopes.pdf: 3796043 bytes, checksum: 70432b9e6f5bb1b00a3971427ddf5a44 (MD5) Previous issue date: 2012-10-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The languages and automata theory is used to obtain the coordinating control logic of automated manufacturing plants. However, there is a lack of standardization to interface MES (Manufacturing Execution System), SCADA (Supervisory Control System and Data Acquisition) and coordination control. This paper investigates the use of languages and automata theory to integrate and implement MES and SCADA with controllers for data acquisition and intervention in the manufacturing plant. This approach aims to achieve consistency between levels as well as the systematic development of interfaces between MES, SCADA and control coordination. Thus, the objective is to reduce the effort for creating and maintaining these systems. Furthermore, it was implemented a tool for modeling and synthesis of the proposed method. For the experiments, it was developed a graphical environment for simulation of manufacturing. The validation was performed by through two experiments in which were modeled and synthesized controller, SCADA and MES according to the proposed method. / A teoria de linguagens e autômatos é utilizada para a obtenção da lógica de controle de coordenação de plantas de manufatura automatizadas. No entanto, há uma carência da padronização das interfaces entre o MES (Sistema de Execução da Manufatura), o SCADA (Controle Supervisório e Aquisição de Dados) e o controle de coordenação. Este trabalho investiga o uso da teoria de linguagens e autômatos para integrar e implementar o MES e o SCADA com os controladores para a aquisição de dados e a intervenção na planta de manufatura. Tal abordagem visa à consistência entre níveis bem como a sistematização do desenvolvimento das interfaces entre MES, SCADA e o controle de coordenação. Com isso, objetiva-se a redução do esforço para a criação e manutenção desses sistemas. Ainda, foi implementada uma ferramenta para a modelagem e síntese conforme o método proposto. Para a realização dos experimentos, foi desenvolvido um ambiente para simulação gráfica da manufatura. A validação foi realizada por meio de dois experimentos, nos quais foram modelados e sintetizados o controlador, o SCADA e o MES segundo o método proposto.