Dissertations / Theses: 'Coordinated control'

1

Ihle, Ivar-Andre Flakstad. "Coordinated Control of Marine Craft." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-945.

Full text

Abstract:

This thesis contains new results on the problem of coordinating a group of vehicles. The main motivation driving this work is the development of control laws that steer individual members of a formation, such that desired group behavior emerges. Special attention is paid to analysis of coordination issues, in particular formation control of marine craft where robustness to unknown environmental forces is important. Coordinated control applications for marine craft include: underway replenishment, maintaining a formation for increased safety during travel and instrument resolution, and cooperative transportation. A review of formation control structures is given, together with a discussion of special issues that arise in coordination of independent vehicles.

The main contributions of this thesis may be grouped into two categories:

• Path-following designs for controlling a group of vehicles

• Multi-body motivated formation modeling and control

A previously developed path following design is used to control a group of vehicles by synchronizing the individual path parameters. The path following design is advantageous since the path parameter, i.e., that parameter which determines position along a path, is scalar; hence coordination is achieved with a little amount of real-time communication. The path following design is also extended to the output-feedback case for systems where only parts of the state vector are known. The path following scheme is exploited further in a passivity-based design for coordination where the structural properties render an extended selection of functions for synchronization available. Performance and robustness properties in different operational conditions can be enhanced with a careful selection of these functions. Two designs are presented; a cascaded interconnection where a consensus system provides synchronized path parameters as input to the individual path following systems renders time-varying formations possible and increases robustness to communication problems; a feedback interconnection which is more robust to vehicle failures. Both designs are extended to sampled-data designs where plant and controller dynamics are updated in continuous-time and path parameters are exchanged over a communication network where transmission occurs at discrete intervals. Bias estimation is included to provide integral action against slowlyvarying environmental forces and model uncertainties.

A scheme for formation modeling and control, inspired by analytical mechanics of multi-body systems and Lagrangian multipliers, is proposed. In this approach to formation control, various formation behaviors are determined by imposing constraint functions on group members. Several examples illustrate these formation behaviors. The stabilization scheme presented is made more robust with respect to unknown time-varying disturbances. In addition, the scheme is extended towards adaptive estimation of unknown plant and parameters. Furthermore, it can be applied with no major modifications to the case of position control for a single vehicle.

The formation control scheme is such that it may be used in combination with a set of position control laws for a single vessel, thus enabling the designer to choose from a large class of control laws available in the literature. The input-to-state stability (ISS) framework is utilised to investigate robustness to environmental and communication disturbances. A loop-transform, together with the ISS framework, yields an upper bound on the inter-vessel time delay below which formation stability is maintained.

APA, Harvard, Vancouver, ISO, and other styles

2

Kang, Keunmo. "Information in coordinated system control." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3320961.

Full text

Abstract:

Thesis (Ph. D.)--University of California, San Diego, 2008.
Title from first page of PDF file (viewed October 3, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 120-123).

APA, Harvard, Vancouver, ISO, and other styles

3

Kalaycioglu, Banu. "Control of coordinated multiple robot manipulators." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61095.

Full text

Abstract:

This thesis investigates the issues of dynamical modelling, control and load distribution for coordinated multiple robot manipulators. An analysis of the load distribution problem for k coordinating robots handling a single payload is carried out and an optimal load sharing algorithm is developed. The algorithm calculates the minimum norms of the joint torques and the contact forces. The algorithm is based on an optimization scheme which minimizes a quadratic cost function associated with the joint torques and contact force vectors for the coordinating robot arms with the constraint of robot equations for a given trajectory of the payload. The developed algorithm is found to be very efficient in terms of computational requirements in comparison with the existing load distribution algorithms. Some of the comparative simulation results are provided. The developed scheme is very attractive for real time applications.
The theory of position control for coordinated multiple manipulator is studied. The main objective of this study is to develop a multiple arm load sharing (with minimum norms) position controller. (Abstract shortened by UMI.)

APA, Harvard, Vancouver, ISO, and other styles

4

Wang, Jiabin. "Coordinated control of multiple robotic maniputators." Thesis, University of East London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241957.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Ahmad, Tanvir. "Wind farm coordinated control and optimisation." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12323/.

Full text

Abstract:

This thesis develops and implements computationally efficient and accurate wind farm coordinated control strategies increasing energy per area by mitigating wake losses. Simulations with data from the Brazos, Le Sole de Moulin Vieux (SMV) and Lillgrund wind farms show an increase of up to 8% in farm production and up to 6% in efficiency. A live field implementation of coordinated control strategies show that curtailing upstream turbine by up to 17% in full or near-full wake conditions can increase downstream turbine’s production by up to 11%. To the best knowledge of the author, this is the first practical implementation of Light Detection And Ranging (LiDAR) based coordinated control strategies in an operating wind farm. With coordinated control, upstream turbines are curtailed using coefficient of power or yaw offsets in such a way that the decrease in upstream turbines’ production is less than the increase in downstream turbines’ production resulting in net gain. This optimum curtailment is achieved with on-line coordinated control which requires an accurate and fast processing wind deficit model and an optimiser which achieves the desired results with high processing speed using minimum overheads. Performance evaluation of carefully selected optimisers was undertaken using an objective function developed for increasing farm production based on coordinated control. This evaluation concluded that Particle Swarm Optimisation (PSO) is the most suitable optimiser for on-line coordinated control due to its high processing speed, computational efficiency and solution quality. The standard Jensen model was used as a starting point for developing a fast processing and accurate wind deficit model referred to as the Turbulence Intensity based Jensen Model (TI-JM), taking wake added turbulence intensity and deep array effect into consideration. The TI-JM uses free-stream and wake-added turbulence intensities for predicting effective values of wake decay coefficients deep inside the farm. This model is validated using WindPRO and data from three wind farms case studies as benchmarks. A methodology for assessing the impact of wakes on farm production is developed. This methodology visualises wake effects (in 360°) by calculating power production using data from the wind farms (case-studies). The wake affected wind conditions are further analysed by calculating relative efficiency. The innovative coordinated control strategies are evaluated using data from the wind farms case studies and WindPRO as benchmarks. A live field implementation of coordinated control strategies demonstrated that the production of downstream turbines can be increased by curtailing upstream turbines. This field setup consisted of two operating wind turbines equipped with modern LiDAR. Analyses of the high frequency real time data were performed comparing field results with simulations. It was found that simulations are in good agreement (within a range of 1.5%) with field results.

APA, Harvard, Vancouver, ISO, and other styles

6

SARAF, ADITYA. "ROBUST FLIGHT CONTROL FOR COORDINATED TURNS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060883331.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Abel, Ryan Orlin. "The coordinated control of autonomous agents." Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/772.

Full text

Abstract:

This thesis considers the coordinated control of autonomous agents. The agents are modeled as double integrators, one for each Cartesian dimension. The goal is to force the agents to converge to a formation specified by their desired relative positions. To this end a pair of one-step-ahead optimization based control laws are developed. The control algorithms produce a communication topology that mirrors the geometric formation topology due to the careful choice of the minimized cost functions. Through this equivalence a natural understanding of the relationship between the geometric formation topology and the communication infrastructure is gained. It is shown that the control laws are stable and guarantee convergence for all viable formation topologies. Additionally, velocity constraints can be added to allow the formation to follow fixed or arbitrary time dependent velocities. Both control algorithms only require local information exchange. As additional agents attach to the formation, only those agents that share position constraints with the joining agents need to adjust their control laws. When redundancy is incorporated into the formation topology, it is possible for the system to survive loss of agents or communication channels. In the event that an agent drops out of the formation, only the agents with position interdependence on the lost agent need to adjust their control laws. Finally, if a communication channel is lost, only the agents that share that communication channel must adjust their control laws. The first control law falls into the category of distributed control, since it requires either the global information exchange to compute the formation size or an a priori knowledge of the largest possible formation. The algorithm uses the network size to penalize the control input for each formation. When using a priori knowledge, it is shown that additional redundancy not only adds robustness to loss of agents or communication channels, but it also decreases the settling times to the desired formation. Conversely, the overall control strategy suffers from sluggish response when the network is small with respect to the largest possible network. If global information exchange is used, scalability suffers. The second control law was developed to address the negative aspects of the first. It is a fully decentralized controller, as it does not require global information exchange or any a priori knowledge.

APA, Harvard, Vancouver, ISO, and other styles

8

Anveden, Hertzberg Naomi. "Coordinated Control for Multiple Autonomous Underwater Vehicles." Thesis, KTH, Reglerteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-152207.

Full text

Abstract:

This thesis discusses self- and event-triggered control for collective motion of autonomous underwater vehicles, for which rules are derived and analysed. The purpose is to enable coordinated underwater motion for agents that can not update their knowledge of the states of the group while submerged. A selftriggered control strategy is studied in which a designated leader agent broadcasts the upcoming waypoints for all agents, based on their desired position relative the leader. A Lyapunov based event-triggered approach is also studied using a potential based control strategy. Stability and convergence problems are discussed as well as the suitability of the control strategies based on feasible inter-surfacing times for the agents. Simulations illustrate the characteristics of the control strategies.

APA, Harvard, Vancouver, ISO, and other styles

9

Spofford, John Rawson. "Coordinated control of a free-flying teleoperator." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14570.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Jin, Zhipu Murray Richard M. "Coordinated control for networked multi-agent systems /." Diss., Pasadena, Calif. : Caltech, 2007. http://resolver.caltech.edu/CaltechETD:etd-09182006-162259.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Azhar, Muhammad Saad Bin, and Ammad Aslam. "Multiple Coordinated Information Visualization Techniques in Control Room Environment." Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-1198.

Full text

Abstract:

Presenting large amount of Multivariate Data is not a simple problem. When there are multiple correlated variables involved, it becomes difficult to comprehend data using traditional ways. Information Visualization techniques provide an interactive way to present and analyze such data. This thesis has been carried out at ABB Corporate Research, Västerås, Sweden. Use of Parallel Coordinates and Multiple Coordinated Views was has been suggested to realize interactive reporting and trending of Multivariate Data for ABB’s Network Manager SCADA system. A prototype was developed and an empirical study was conducted to evaluate the suggested design and test it for usability from an actual industry perspective. With the help of this prototype and the evaluations carried out, we are able to achieve stronger results regarding the effectiveness and efficiency of the visualization techniques used. The results confirm that such interfaces are more effective, efficient and intuitive for filtering and analyzing Multivariate Data.

APA, Harvard, Vancouver, ISO, and other styles

12

Bjerkeng, Magnus Christian. "Coordinated Control with Obstacle Avoidance for Robot Manipulators." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9124.

Full text

Abstract:

This thesis addresses the problem of robot synchronization with obstacle avoidance. While these two fields have been studied extensively on their own, they have not yet been considered together as one problem. This thesis is divided roughly into four parts which are to some extent self contained. The theory is presented in a narrative that culminates with the stability proof of the proposed controller. Examples and figures are used in order to keep the material manageable and readable. The introductory part of the thesis consists of chapters 1 and 2. We present the notation and some mathematical background which is necessary for the theoretical analysis. We go on to review the diversity of ways in which one may approach this problem from a control design standpoint. We derive the robot dynamical model in chapter 3 as well as solve other modeling specific problems. This chapter is of little theoretical interest, but is needed to implement a simulator on which we may test our controller. This chapter contains no new contributions but can be read as a guide to robot modeling. The first contributions in this thesis are found in chapter 4 where we propose a real time implementable solution for solving the shortest distance estimation problem. It is important to know the distance to an obstacle in order to avoid it. The solution is a dynamic implementation of a steepest descent optimization scheme which is suitable to run on-line. Chapter 5 is an introduction to the involved control design found in chapter 6. We review results from obstacle avoidance literature and argue for our choice of using the task space control design method. The main contribution of this thesis is found in chapter 6. A controller is developed and is shown to produce a stable closed loop system. We first develop a controller considering only collision for the end effector, and then we extend this to work with full robot collision. The response of the robot is such that it will track a reference trajectory whenever it is locally possible. When one cannot track the reference trajectory because of obstacles hindering the movement, then the trajectory is tracked in all directions in which the robot can move freely. The controller is simple and elegant, and does not rely on heuristics common in traditional solutions to obstacle avoidance control.

APA, Harvard, Vancouver, ISO, and other styles

13

Eriksson, Robert. "Coordinated Control of HVDC Links in Transmission Systems." Doctoral thesis, KTH, Elektriska energisystem, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-30625.

Full text

Abstract:

Dynamic security limits the power transfer capacity between regions and therefore has an economic impact. The power modulation control of high-voltage direct current (HVDC) links can improve the dynamic security of the power system. Having several HVDC links in a system creates the opportunity to coordinate such control, and coordination also ensures that negative interactions do not occur among the controllable devices. This thesis aims to increase dynamic security by coordinating HVDC links, as an alternative to decreasing the transfer capacity. This thesis contributes four control approaches for increasing the dynamic stability, based on feedforward control, adaptive control, optimal control, and exact-feedback linearization control. Depending on the available measurements, dynamic system model, and system topology, one of the developed methods can be applied. The wide-area measurement system provides the central controller with real-time data and sends control signals to the HVDC links. The feedforward controller applies rapid power dispatch, and the strategy used here is to link the N-1 criterion between two systems. The adaptive controller uses the modal analysis approach; based on forecasted load paths, the controller gains are adaptively adjusted to maximize the damping in the system. The optimal controller is designed based on an estimated reduced-order model; system identification develops the model based on the system response. The exact-feedback linearization approach uses a pre-feedback loop to cancel the nonlinearities; a stabilizing controller is designed for the remaining linear system. The conclusion is that coordinating the HVDC links improves the dynamic stability, which makes it possible to increase the transfer capacity. This conclusion is also supported by simulations of each control approach.
QC 20110302

APA, Harvard, Vancouver, ISO, and other styles

14

Falconi, Riccardo <1978&gt. "Coordinated Control of Robotic Swarms in Unknown Environments." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1657/.

Full text

Abstract:

This thesis gathers the work carried out by the author in the last three years of research and it concerns the study and implementation of algorithms to coordinate and control a swarm of mobile robots moving in unknown environments. In particular, the author's attention is focused on two different approaches in order to solve two different problems. The first algorithm considered in this work deals with the possibility of decomposing a main complex task in many simple subtasks by exploiting the decentralized implementation of the so called \emph{Null Space Behavioral} paradigm. This approach to the problem of merging different subtasks with assigned priority is slightly modified in order to handle critical situations that can be detected when robots are moving through an unknown environment. In fact, issues can occur when one or more robots got stuck in local minima: a smart strategy to avoid deadlock situations is provided by the author and the algorithm is validated by simulative analysis. The second problem deals with the use of concepts borrowed from \emph{graph theory} to control a group differential wheel robots by exploiting the Laplacian solution of the consensus problem. Constraints on the swarm communication topology have been introduced by the use of a range and bearing platform developed at the Distributed Intelligent Systems and Algorithms Laboratory (DISAL), EPFL (Lausanne, CH) where part of author's work has been carried out. The control algorithm is validated by demonstration and simulation analysis and, later, is performed by a team of four robots engaged in a formation mission. To conclude, the capabilities of the algorithm based on the local solution of the consensus problem for differential wheel robots are demonstrated with an application scenario, where nine robots are engaged in a hunting task.

APA, Harvard, Vancouver, ISO, and other styles

15

McNeilly, Gordon. "Coordinated control of hot strip tandem rolling mill." Thesis, University of Strathclyde, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366772.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Obradovic, Danilo. "Coordinated Frequency Control Between Interconnected AC/DC Systems." Licentiate thesis, KTH, Elkraftteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280156.

Full text

Abstract:

With ambitions of reducing the environmental pollution, power systems integrate larger shares of Renewable Energy Sources (RES) to phase out conventional thermal and nuclear generators. Since RES (such as wind and solar power) are connected to the grid through power electronics devices, they do not inherently contribute to system inertia. With decreasing inertia, the Instantaneous Frequency Deviation (IFD), which follows a power unbalance, is significantly impacted. Frequency Containment Reserves (FCR) are designed to provide a fast dynamic response, counteract power imbalances and stabilize the frequency within a short time interval. Besides inertia, the significant factors affecting frequency behavior are the available amount of FCR and the capability of their fast and stable response. System operators define the list of requirements that a generating unit has to satisfy to participate in FCR. Generators, which are the major part of FCR, have different governors and turbines properties. This study assesses the dynamical performance of typical generators in both open-loop testing and closed-loop varying inertia systems. The goal is to evaluate if specific FCR requirements present a sufficient condition for the desired response, and which governor properties are capable of satisfying them. As an additional, and sometimes necessary, support to FCR, HVDC interconnections are utilized in the form of Emergency Power Control (EPC). This thesis investigates which of the EPC methods performs appropriately in terms of IFD improvement, closed-loop stability, and power and energy provided. The analysis is a continuation from the previous investigation on FCR, and mainly compare two EPC methods related to Nordic Power System (NPS) test case: ramp/step method which is currently implemented in the NPS, and droop frequency-based EPC, proposed by this study for the future operation in the NPS. Apart from ensuring a proper system frequency response, the influence of implemented HVDC supplementary active power control is analyzed to rotor angle stability. In further, this thesis presents a comprehensive analysis of the impact that proposed HVDC supplementary power control has on the linearized dynamics of power systems. By building a generic system, this analytical study is the first of its kind that includes both higher order generator dynamics, and local angle/frequency input of the controller. The methodological approach here analytically formulates the impact the HVDC supplementary control has mainly on the generator synchronizing and damping torque components. The positive impact of the droop frequency-based HVDC power support is highlighted using both single and multi-machine systems. In that way, the implementation of desired droop frequency-based HVDC control to mainly improve system frequency is motivated furthermore. It shows that a proper HVDC supplementary control may impose the various positive impacts for future variable and low inertia scenarios, and ensure a proper power system sustainability.

QC 20200907

multiDC - Advanced Control and Optimization Methods for AC and HVDC Grids

APA, Harvard, Vancouver, ISO, and other styles

17

Wang, Lei. "Coordinated and non-coordinated control of energy storage for voltage support in low voltage distribution networks." Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3208.

Full text

Abstract:

Energy storage is seen as one of a number of crucial technologies if the integration of renewables in distribution networks increases. The work in this thesis considers how to operate energy storage to overcome issues presented by solar photovoltaic (PV) in low voltage (LV) distribution networks. Two control strategies have been developed and applied in a smart grid laboratory to mitigate voltage rise and reverse power flows caused by PV. The first strategy examines the performance of non-coordinated control of energy storage for voltage support. The second strategy involves coordinating the on-load tap changer (OLTC) and energy storage for voltage support and reducing reverse power flows, and it illustrates that coordinated storage unit is a more effective and viable alternative to upgrading network infrastructure. After considering a single storage unit in the network, strategies for controlling multiple storage units are investigated. The main objective of this method is to solve overvoltage with multiple energy storage in LV networks with a proliferation of PV systems. The scheme is based on voltage sensitivity analysis and a battery aging model which influences which storage units are operated to maintain the network voltage within limits. The battery aging model is included to improve to reduce degradation when operated to resolve voltage excursions thus reducing the maintenance and battery replacement costs. To get a better performance of the storage unit for voltage support, a systematic model that includes the PV generator and the energy storage based on linearized differential equations is constructed. The model was used to examine: the dynamic performance of battery storage systems and their active and reactive power voltage regulation feedback controller; small disturbance of active and reactive power exchange with the power system; a methodology to utilise active and reactive power of the energy storage for voltage support. In summary, the study presented by this thesis shows energy storage can be operated in the LV distribution network where significant amounts of PV generators are installed. It allows distribution network operators to have a deeper understanding of how to operate single and multiple energy storage units in future LV distribution networks.

APA, Harvard, Vancouver, ISO, and other styles

18

Li, Howard. "A Framework for Coordinated Control of Multi-Agent Systems." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2791.

Full text

Abstract:

Multi-agent systems represent a group of agents that cooperate to solve common tasks in a dynamic environment. Multi-agent control systems have been widely studied in the past few years. The control of multi-agent systems relates to synthesizing control schemes for systems which are inherently distributed and composed of multiple interacting entities. Because of the wide applications of multi-agent theories in large and complex control systems, it is necessary to develop a framework to simplify the process of developing control schemes for multi-agent systems.

In this study, a framework is proposed for the distributed control and coordination of multi-agent systems. In the proposed framework, the control of multi-agent systems is regarded as achieving decentralized control and coordination of agents. Each agent is modeled as a Coordinated Hybrid Agent (CHA) which is composed of an intelligent coordination layer and a hybrid control layer. The intelligent coordination layer takes the coordination input, plant input and workspace input. After processing the coordination primitives, the intelligent coordination layer outputs the desired action to the hybrid layer. In the proposed framework, we describe the coordination mechanism in a domain-independent way, as simple abstract primitives in a coordination rule base for certain dependency relationships between the activities of different agents. The intelligent coordination layer deals with the planning, coordination, decision-making and computation of the agent. The hybrid control layer of the proposed framework takes the output of the intelligent coordination layer and generates discrete and continuous control signals to control the overall process. In order to verify the feasibility of the proposed framework, experiments for both heterogeneous and homogeneous Multi-Agent Systems (MASs) are implemented. In addition, the stability of systems modeled using the proposed framework is also analyzed. The conditions for asymptotic stability and exponential stability of a CHA system are given.

In order to optimize a Multi-Agent System (MAS), a hybrid approach is proposed to address the optimization problem for a MAS modeled using the CHA framework. Both the event-driven dynamics and time-driven dynamics are included for the formulation of the optimization problem. A generic formula is given for the optimization of the framework. A direct identification algorithm is also discussed to solve the optimization problem.

APA, Harvard, Vancouver, ISO, and other styles

19

Askins, Stephen Alexander. "Modeling of digital clay for evaluation of coordinated control." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/19541.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Nambiar, Anup Jayaprakash. "Coordinated control and network integration of wave power farms." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/7712.

Full text

Abstract:

Significant progress has been made in the development of wave energy converters (WECs) during recent years, with prototypes and farms of WECs being installed in different parts of the world. With increasing sizes of individual WECs and farms, it becomes necessary to consider the impacts of connecting these to the electricity network and to investigate means by which these impacts may be mitigated. The time-varying and the unpredictable nature of the power generated from wave power farms supplemented by the weak networks to which most of these farms will be connected to, makes the question of integrating a large quantity of wave power to the network more challenging. The work reported here focuses on the fluctuations in the rms-voltage introduced by the connection of wave power farms. Two means to reduce these rms-voltage fluctuations are proposed. In the first method, the physical placement of the WECs within a farm is selected prior to the development of the farm to reduce the fluctuations in the net real power generated. It is shown that spacing the WECs or the line of WECs within a farm at a distance greater than half the peak wavelength and orienting the farm at 90◦ to the dominant wave direction produces a much smoother power output. The appropriateness of the following conclusions has been tested and proven for a wave power farm developed off the Outer Hebrides, using real wave field and network data. The second method uses intelligent reactive power control algorithms, which have already been tested with wind and hydro power systems, to reduce voltage fluctuations. The application of these intelligent control methods to a 6 MW wave power farm connected to a realistic UK distribution network verified that these approaches improve the voltage profile of the distribution network and help the connection of larger farms to the network, without any need for network management or upgrades. Using these control methods ensured the connection of the wave power farm to the network for longer than when the conventional control methods are used, which is economically beneficial for the wave power farm developer. The use of such intelligent voltage - reactive power (volt/VAr) control methods with the wave power farm significantly affects the operation of other onshore voltage control devices found prior to the connection of the farm. Thus, it is essential that the control of the farm and the onshore control devices are coordinated. A voltage estimation method, which uses a one-step-ahead demand predictor, is used to sense the voltage downstream of the substation at the bus where the farm is connected. The estimator uses only measurements made at the substation and historical demand data. The estimation method is applied to identify the operating mode of a wave power farm connected to a generic 11 kV distribution network in the UK from the upstream substation. The developed method introduced an additional level of control and can be used at rural substations to optimise the operation of the network, without any new addition of measuring devices or communication means.

APA, Harvard, Vancouver, ISO, and other styles

21

Hambrick, Joshua Clayton. "Configurable, Coordinated, Model-based Control in Electrical Distribution Systems." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/37792.

Full text

Abstract:

Utilities have been planning, building, and operating electrical distribution systems in much the same way for decades with great success. The electrical distribution system in the United States has been consistently reliable; an impressive feat considering its amazing complexity. However, in recent years, the electrical distribution system landscape has started to undergo drastic changes. Emerging applications of technologies such as distributed generation, communications, and power electronics offer both opportunities and challenges to power system operators as well as customers and developers. In this work, Graph Trace Analysis along with an integrated system model are used to develop algorithms and analysis methods necessary to facilitate the implementation of these new technologies on the electrical distribution system. A penetration limit analysis is developed to analyze the impact of distributed generation on radial distribution feeders. The analysis considers generation location, equipment rating, voltage violations, and flicker to determine the amount of generation that can be safely attached to a circuit. A real-time, hierarchical, model-based control method is developed that coordinates the operation of all control devices on electrical distribution circuits. The controller automatically compensates for changes in circuit topology as well as the addition or removal of control devices from the active circuit. Additionally, the controller allows the integration of modern, "smart" equipment with legacy control devices to facilitate incremental modernization strategies. Finally, a framework is developed to allow the testing of new analysis and control methodologies for electrical distribution systems. The framework can be used to test scenarios over multiple consecutive hourly or sub-hourly time points. The framework is used to demonstrate the effectiveness of the model-based controller versus existing operating methods for a distribution circuit test case.
Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

22

VanDyke, Matthew Clark. "Decentralized Coordinated Attitude Control of a Formation of Spacecraft." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/10015.

Full text

Abstract:

Spacecraft formations offer more powerful and robust space system architectures than single spacecraft systems. Investigations into the dynamics and control of spacecraft formations are vital for the development and design of future successful space missions. The problem of controlling the attitude of a formation of spacecraft is investigated. The spacecraft formation is modelled as a distributed system, where the individual spacecraft's attitude control systems are the local control agents. A decentralized attitude controller utilizing behavior-based control is developed. The global stability of the controller is proven using Lyaponuv stability theory. Convergence of the attitude controller is proven through the use of an invariance argument. The attitude controller's stability and convergence characteristics are investigated further through numeric simulation of the attitude dynamics of the spacecraft formation.
Master of Science

APA, Harvard, Vancouver, ISO, and other styles

23

Eriksson, Robert. "Security-centered Coordinated Control in AC/DC Transmission Systems." Licentiate thesis, Stockholm : Royal Institute of Technology, 2008. http://kth.diva-portal.org/smash/record.jsf?searchId=4&pid=diva2:101.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Xiang, Xianbo. "Coordinated motion control of multiple underactuated autonomous underwater vehicles." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20005.

Full text

Abstract:

Cette thèse traite de la question du contrôle du mouvement d'engins non-holonomes et sous-actionnés évoluant de manière coordonnée et autonome. Les différentes approches considérées sont le suivi de trajectoire (Trajectory Tracking TT) et le suivi de chemin (path following PF). Une nouvelle méthode de contrôle est proposée. Dénommée Path-Tracking (PT), elle permet de cumuler les avantages de chacune des deux précédentes méthodes, permettant de cumuler la souplesse de la convergence induite par le suivi de chemin avec le respect des contraintes temporelles du suivi de trajectoire. L'étude et la réalisation de la commande démarre avec l'étude du cas du robot nonholonome de type Unicycle' et se base sur les principes de Lyapunov' et de Backstepping'. Ces premiers résultats sont ensuite étendus au cas d'un véhicule sous-marin sous-actionné de type AUV (Autonomous Underwater Vehicle'), en analysant les similarités cinématiques entre ces deux types de véhicules. De plus, il est montré la nécessité de prendre en compte les propriétés dynamiques du système de type AUV, et la condition de Stern dominancy' est établie de façon à garantir que le problème est bien posé et ainsi que la commande soit aisément calculable. Dans la cas d'un système marin sur-actionné, qui peut ainsi effectuer des tâches de navigation au long cours et de positionnement désiré (Station keeping'), une commande hybride est proposée. Enfin, la question du contrôle coordonné d'une formation d'engins marin est abordée. Les colutions de commande pour les taches de suivi de chemin coordonné (coordinated path following') et de coordinated path tracking' sont proposées. Les principes du leader-follower' et la méthode des structures virtuelles sont ainsi traitées dans un cadre de contrôle centralisé, et le cas décentralisé est traité en utilisant certains principes de théorie des graphes
In this dissertation, the problems of motion control of underactuated autonomous vehicles are addressed,namely trajectory tracking (TT), path following (PF), and novelly proposed path tracking whichblending the PF and TT together in order to achieve smooth spatial convergence and tight temporalperformance as well.The control design is firstly started from the benchmark case of nonholonomic unicycle-type vehicles,where the Lyapunov-based design and backstepping technique are employed, and then it is extendedto the underactuated AUVs based on the similarity between the control inputs of two kinds of vehicles.Moreover, dealing with acceleration of side-slip angle is highlighted and stern-dominant property of AUVsis standing out in order to achieve well-posed control computation. Transitions of motion control fromunderactuated to fully actuated AUVs are also proposed.Finally, coordinated formation control of multiple autonomous vehicles are addressed in two-folds,including coordinated paths following and coordinated paths tracking, based on leader-follower andvirtual structure method respectively under the centralized control framework, and then solved underdecentralized control framework by resorting to algebraic graph theory

APA, Harvard, Vancouver, ISO, and other styles

25

Kraus, Dustan Paul. "Coordinated, Multi-Arm Manipulation with Soft Robots." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7066.

Full text

Abstract:

Soft lightweight robots provide an inherently safe solution to using robots in unmodeled environments by maintaining safety without increasing cost through expensive sensors. Unfortunately, many practical problems still need to be addressed before soft robots can become useful in real world tasks. Unlike traditional robots, soft robot geometry is not constant but can change with deflation and reinflation. Small errors in a robot's kinematic model can result in large errors in pose estimation of the end effector. This error, coupled with the inherent compliance of soft robots and the difficulty of soft robot joint angle sensing, makes it very challenging to accurately control the end effector of a soft robot in task space. However, this inherent compliance means that soft robots lend themselves nicely to coordinated multi-arm manipulation tasks, as deviations in end effector pose do not result in large force buildup in the arms or in the object being manipulated. Coordinated, multi-arm manipulation with soft robots is the focus of this thesis. We first developed two tools enabling multi-arm manipulation with soft robots: (1) a hybrid servoing control scheme for task space control of soft robot arms, and (2) a general base placement optimization for the robot arms in a multi-arm manipulation task. Using these tools, we then developed and implemented a simple multi-arm control scheme. The hybrid servoing control scheme combines inverse kinematics, joint angle control, and task space servoing in order to reduce end effector pose error. We implemented this control scheme on two soft robots and demonstrated its effectiveness in task space control. Having developed a task space controller for soft robots, we then approached the problem of multi-arm manipulation. The placement of each arm for a multi-arm task is non-trivial. We developed an evolutionary optimization that finds the optimal arm base location for any number of user-defined arms in a user-defined task or workspace. We demonstrated the utility of this optimization in simulation, and then used it to determine the arm base locations for two arms in two real world coordinated multi-arm manipulation tasks. Finally, we developed a simple multi-arm control scheme for soft robots and demonstrated its effectiveness using one soft robot arm, and one rigid robot with low-impedance torque control. We placed each arm base in the pose determined by the base placement optimization, and then used the hybrid servoing controller in our multi-arm control scheme to manipulate an object through two desired trajectories.

APA, Harvard, Vancouver, ISO, and other styles

26

Meegahapola, Lasantha. "Stability analysis and coordinated control strategies during high wind penetration." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534620.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Pal, Anamitra. "Coordinated Control of Inter-area Oscillations using SMA and LMI." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/41229.

Full text

Abstract:

The traditional approach to damp inter-area oscillations is through the installation of Power System Stabilizers (PSSs) which provide damping control action through excitation control systems of the generating units. However, study of recent blackouts has shown that the control action provided by a PSS alone is not sufficient for damping oscillations in modern power systems which operate under stressed conditions. An integrated form of control using remote measurements to coordinate the different control elements present in the system is the need of the hour. One way of implementing such a coordinated control is through the development of a Linear Matrix Inequality (LMI)-based polytopic model of the system that guarantees pole placement for a variety of operating conditions. The size of the polytopic formulation is an issue for application of LMIs to large systems. The use of Selective Modal Analysis (SMA) alleviates this problem by reducing the size of the system. The previous attempts have used a model containing all the and modes, with SMA being used to eliminate all the other states. In practical applications the resulting system was still found to be too large to use in a polytopic model. This thesis presents an algorithm to reduce the size of the system to the relevant modes of oscillations. A 16 machine, 68 bus equivalent model of the New England-New York interconnected power system is used as the test case with DC lines and SVCs acting as the control. The algorithm is then applied to a 127-bus equivalent model of the WECC System. The use of ESDs as a form of control is also demonstrated. The results indicate that the proposed control successfully damps the relevant modes of oscillations without negatively damping the other modes. The control is then transferred to a more detailed 4000+ bus model of the WECC system to realize its performance on real-world systems.
Master of Science

APA, Harvard, Vancouver, ISO, and other styles

28

Thepparat, Pakorn. "Analysis of the combined and coordinated control method for HVDC transmission." Aachen Shaker, 2010. http://d-nb.info/1001789059/04.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Ibanez, Aurélien. "Emergence of complex behaviors from coordinated predictive control in humanoid robotics." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066325/document.

Full text

Abstract:

Le problème de commande motrice de systèmes exécutant des activités multi-objectifs et fortement contraintes est à résoudre pour permettre l’émergence de comportements performants et robustes ; l’élaboration de stratégies complexes de coordination motrice est critique pour en assurer les performances, faisabilité et sécurité.Bien que les approches de commande prédictive multi-objectifs permettent la définition de stratégies complexes et sous contraintes coordonnant l’activité motrice du système, leur coût de calcul est un inconvénient critique à leur application.Le travail présenté dans ce manuscrit vise à considérer des techniques de commande prédictive multi-objectifs pour des applications pratiques à la robotique humanoïde.Une architecture de commande est alors proposée sous la forme d’un contrôleur multi-objectif à deux niveaux, exploitant les avantages respectifs des formulations prédictive et instantanée.La contribution de ce travail prend la forme de la validation des avantages d’une telle approche dans son développement pour des défis pratiques, en simulation et implémentation temps-réel, sur les robots iCub et TORO ainsi que sur des modèles d’humain.Le coût de calcul du niveau prédictif est contenu par l’introduction de problèmes réduits, permettant la formulation avantageuse de problèmes de commande au travers de programmes en nombres entiers mixtes et de distributions séquentielles et parallèles.Malgré les approximations sur la dynamique du système au niveau prédictif, des comportements complexes émergent, exploitant des stratégies de coordination entre objectifs et contraintes conflictuels pour augmenter les performances et robustesse face à des perturbations
Rising to the challenge of motor control for systems involved in multi-objective and highly-constrained activities is a requirement to enable the emergence of efficient and robust behaviors; the elaboration of complex motor coordination strategies is critical in ensuring performance, feasibility and safety.Although multi-objective predictive approaches enable the definition of complex and constrained strategies coordinating the motor activity of the system, their computational cost is a critical drawback from practical applications.The work presented in this dissertation aims at considering multi-objective predictive control for feasible and practical applications to humanoid robotics.A control architecture is proposed to this purpose as a multi-objective, two-layered controller exploiting the respective advantages of predictive and instantaneous formulations.The contribution of this work takes the form of the validation of the benefits from such an approach in its development for practical challenges and applications, in simulation and real-time implementation, on the iCub and TORO robots and virtual human models.Computational demand of the predictive level is contained with the introduction of reduced multi-objective predictive problems, enabling computationally-favorable formulations of the control problem using mixed-integer programming and sequential and parallel distributions.Despite the resulting approximations on the dynamics of the system at the predictive level, complex behaviors are emerging, exploiting elaborate coordination strategies between conflicting objectives and constraints to increase performance and robustness against disturbances

APA, Harvard, Vancouver, ISO, and other styles

30

Tumeh, Zuheir Shafik. "Real time coordinated control of two robot arms in six dimensions." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/13910.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Gordon, Brandon W. (Brandon William). "Coordinated control of two macro/micro manipulators for fiber pigtailing automation." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10926.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Sunada, Craig Daniel. "Coordinated Jacobian transpose control and its application to a climbing machine." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37529.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Leban, Frank A. "Coordinated control of a planar dual crane non-fully restrained system." Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/dissert/2008/Dec/08Dec%5FLeban.pdf.

Full text

Abstract:

Dissertation (PhD in Mechanical Engineering)--Naval Postgraduate School, December 2008.
Thesis Advisor(s): Healey, Anthony. "December 2008." Description based on title screen as viewed on 29 January 2009. Includes bibliographical references (p. 357-362). Also available in print.

APA, Harvard, Vancouver, ISO, and other styles

34

Khan, Sheroz. "Coordinated protection and control in power systems : an expert system approach to interlocking management." Thesis, University of Strathclyde, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338913.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Holmberg, Per. "Sensor Fusion with Coordinated Mobile Robots." Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1717.

Full text

Abstract:

Robust localization is a prerequisite for mobile robot autonomy. In many situations the GPS signal is not available and thus an additional localization system is required. A simple approach is to apply localization based on dead reckoning by use of wheel encoders but it results in large estimation errors. With exteroceptive sensors such as a laser range finder natural landmarks in the environment of the robot can be extracted from raw range data. Landmarks are extracted with the Hough transform and a recursive line segment algorithm. By applying data association and Kalman filtering along with process models the landmarks can be used in combination with wheel encoders for estimating the global position of the robot. If several robots can cooperate better position estimates are to be expected because robots can be seen as mobile landmarks and one robot can supervise the movement of another. The centralized Kalman filter presented in this master thesis systematically treats robots and extracted landmarks such that benefits from several robots are utilized. Experiments in different indoor environments with two different robots show that long distances can be traveled while the positional uncertainty is kept low. The benefit from cooperating robots in the sense of reduced positional uncertainty is also shown in an experiment.

Except for localization algorithms a typical autonomous robot task in the form of change detection is solved. The change detection method, which requires robust localization, is aimed to be used for surveillance. The implemented algorithm accounts for measurement- and positional uncertainty when determining whether something in the environment has changed. Consecutive true changes as well as sporadic false changes are detected in an illustrative experiment.

APA, Harvard, Vancouver, ISO, and other styles

36

Dunnigan, Matthew W. "An investigation of the dynamic coupling between a manipulator and anunderwater vehicle." Thesis, Heriot-Watt University, 1994. http://hdl.handle.net/10399/1417.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Hug-Glanzmann, Gabriela. "Coordinated Power Flow Control to enhance steady-state security in power systems /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17586.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Alimisi, Varvara. "Improved coordinated automatic voltage control in power grids through complex network analysis." Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3127.

Full text

Abstract:

Automatic and Co-ordinated Voltage Regulation (CVR) contributes significantly to economy and security of transmission grids. The role of CVR will become more critical as systems are operated closer to their capacity limits due to technical, economic and environmental reasons. CVR has 1 min resolution and owing to the inherent complexity of the task, CVR is enabled through zoning-based Reduced Control Models (RCM) i.e. simplified models of the network suitable for Voltage Control. RCM not only enables CVR bus also affects its performance and robustness. This thesis contributes towards improved CVR through thorough investigation of the RCM. As a starting point, with current power systems structure in mind, this work investigates static RCM schemes (i.e. fixed Reduced Control Model for all network configurations). To that end this thesis develops: (1) a novel generic framework for CVR modelling and evaluation and (2) new zoning-based RCM approaches using Complex Network Analysis. The evaluation of CVR in conjunction with both static and adaptive RCM schemes are based on a novel framework for CVR modelling and evaluation. This framework is generic and can be used to facilitate the selection and design of any of the CVR components. As a next step, due to the fact that a single RCM cannot be optimal for all network configurations, adaptive RCM (i.e. RCM determined in an online event driven fashion) is investigated using the proposed framework. This concerns future transmission grids where RCM is driven by the need for reliability rather than economy of measurement points at a planning phase. Lastly, this thesis examines zone division in an interconnected system ranging from EHV down to MV, and assesses the required degree of co-ordination for the voltage control of these zones. Essentially, this last item extends the scope of this work’s contributions beyond a single transmission-level Independent System Operator (ISO).

APA, Harvard, Vancouver, ISO, and other styles

39

Mu, Bin. "System modelling, identification and coordinated control design for an articulated forestry machine." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29618.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Mu, Bin. "System modelling, identification and coordinated control design for an articulated forestry machine." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27245.

Full text

Abstract:

This thesis describes the modelling of electrohydraulic actuation systems of a prototype forestry vehicle, the experimental identification of the dynamic models parameters and control strategies for forestry operations.
The linear graph method is selected to derive comprehensive models of three electrohydraulic actuation subsystems, i.e. the swing, boom and stick subsystems, on the vehicle based on modelling of individual components. A new approach is proposed, then, to integrate rigid-body dynamic models with the actuator dynamic models to result in a complete machine model.
Off-line parameter identification procedures are used, including the least-square method. A series of experiments is performed to obtain numerical values for the parameters involved in the system models. The experimental setups are described in detail and new procedures are explained. The model validation studies show that the mathematical models closely represent the dynamic characteristics of the forestry machine.
The concept of coordinated control in teleoperation is studied. The resolved motion rate control strategy shows superiority over conventional joint-based control in heavy-duty forestry machines. Two inverse Jacobian manipulator control schemes, based on velocity and on position servo schemes, are introduced and evaluated under various operating conditions. The results provide guidelines for the design and implementation of manipulator controllers on a forestry machine.

APA, Harvard, Vancouver, ISO, and other styles

41

Hung, Min-Hsiung. "Dynamic control and simulation of actively-coordinated robotic terrain-adaptive wheeled vehicles /." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488188894440112.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Wise, Richard. "UAV guidance control laws for autonomous coordinated tracking of a moving ground target /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/9959.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Thepparat, Pakorn [Verfasser]. "Analysis of the Combined and Coordinated Control Method for HVDC Transmission / Pakorn Thepparat." Aachen : Shaker, 2010. http://d-nb.info/1122546165/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Paaso, Esa A. "Coordinated Voltage and Reactive Power Control of Power Distribution Systems with Distributed Generation." UKnowledge, 2014. http://uknowledge.uky.edu/ece_etds/40.

Full text

Abstract:

Distribution system voltage and VAR control (VVC) is a technique that combines conservation voltage reduction and reactive power compensation to operate a distribution system at its optimal conditions. Coordinated VVC can provide major economic benefits for distribution utilities. Incorporating distributed generation (DG) to VVC can improve the system efficiency and reliability. The first part of this dissertation introduces a direct optimization formulation for VVC with DG. The control is formulated as a mixed integer non-linear programming (MINLP) problem. The formulation is based on a three-phase power flow with accurate component models. The VVC problem is solved with a state of the art open-source academic solver utilizing an outer approximation algorithm. Applying the approach to several test feeders, including IEEE 13-node and 37-node radial test feeders, with variable load demand and DG generation, validates the proposed control. Incorporating renewable energy can provide major benefits for efficient operation of the distribution systems. However, when the number of renewables increases the system control becomes more complex. Renewable resources, particularly wind and solar, are often highly intermittent. The varying power output can cause significant fluctuations in feeder voltages. Traditional feeder controls are often too slow to react to these fast fluctuations. DG units providing reactive power compensation they can be utilized in supplying voltage support when fluctuations in generation occur. The second part of this dissertation focuses on two new approaches for dual-layer VVC. In these approaches the VVC is divided into two control layers, slow and fast. The slow control obtains optimal voltage profile and set points for the distribution control. The fast control layer is utilized to maintain the optimal voltage profile when the generation or loading suddenly changes. The MINLP based VVC formulation is utilized as the slow control. Both local reactive power control of DG and coordinated quadratic programming (QP) based reactive power control is considered as the fast control approaches. The effectiveness of these approaches is studied with test feeders, utility load data, and fast-varying solar irradiance data. The simulation results indicate that both methods achieve good results for VVC with DG.

APA, Harvard, Vancouver, ISO, and other styles

45

CID, PEDRO HENRIQUE SILVA. "VOLTAGE STABILITY ASSESSMENT INDEXES FOR SYSTEMS WITH LOCAL, REMOTE AND COORDINATED VOLTAGE CONTROL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2013. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=23512@1.

Full text

Abstract:

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
A crescente demanda de energia elétrica, associada a limitações na expansão do sistema de transmissão, resulta na operação dos sistemas elétricos cada vez mais próxima de seus limites, tornando-os vulneráveis a problemas de estabilidade de tensão. Neste contexto, o desenvolvimento de métodos para avaliação do carregamento da rede de transmissão tornou-se fundamental para que se possa compreender o funcionamento do sistema nestas condições, bem como possibilitar sua operação com maior confiabilidade e segurança. No presente trabalho é apresentada a formulação não-clássica para o controle de tensão local, remoto e coordenado, utilizada na solução do problema do fluxo de potência. A partir desta formulação, foi realizado o estudo da teoria associada à avaliação do carregamento da rede de transmissão considerando não só barras de carga e barras de tensão controlada localmente, mas também barras controladoras e de tensão controlada em sistemas com controle de tensão remoto e coordenado. Para essas barras, foram deduzidos índices de avaliação das condições de estabilidade de tensão, os quais indicam a região de operação de cada barra na curva para phi constante no plano SV, a margem em MVA para o máximo carregamento e a importância relativa entre as barras. Exemplos numéricos são apresentados demonstrando a aplicabilidade dos índices propostos.
The growing demand for electricity, coupled with the limitations on the transmission system’s expansion, results in the operation of power systems ever closer to their limits, making them vulnerable to voltage stability problems. In this context, the development of methods to evaluate the loading of the transmission system became essential so that you can understand the operation of the system under these conditions, and to enable its operation with greater reliability and security. This work presents the formulation for the non-classical local, remote and coordinated voltage control, used in solving the problem of load flow. From this formulation, the study of the theory associated with the assessment of the loading of the transmission system was conducted considering not only load buses and locally voltage controlled buses, but also voltage controlling and controlled buses in systems with remote and coordinated voltage control. For these buses were deducted evaluation indexes of voltage stability conditions, which indicate the operating region of each bus in the S-V curve, the margin in MVA for maximum loading and the relative importance between the buses. Numerical examples are presented demonstrating the applicability of the proposed indexes.

APA, Harvard, Vancouver, ISO, and other styles

46

[Verfasser], Pakorn Thepparat. "Analysis of the Combined and Coordinated Control Method for HVDC Transmission / Pakorn Thepparat." Aachen : Shaker, 2010. http://nbn-resolving.de/urn:nbn:de:101:1-201701012279.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Ghazanfari, A. (Amin). "Coordinated beamforming and power control for network controlled Device-to-Device (D2D) communication." Master's thesis, University of Oulu, 2014. http://urn.fi/URN:NBN:fi:oulu-201401111003.

Full text

Abstract:

Since the integration of data services into cellular communications, cellular operators are struggling to harness the overwhelming data traffic on their networks. Underlay Device-to-Device (D2D) communication is a new and promising paradigm which allows proximate mobile users to have direct communication over the cellular spectrum that may be reused by other cellular users in the same cell. This new paradigm is proposed to assist the cellular operators to deal with the booming demand of mobile users. Recent studies have shown that underlay D2D communication significantly increases the cellular network capacity, and enables cellular operators to support rich multimedia services. However, reusing cellular resources for both D2D and cellular communication introduces interference issues. In such systems, interference management is of utmost importance because improper interference coordination may lead to a self-destructive network. Power control and beamforming appears to be viable techniques for interference management which can also be used to enhance the energy efficiency of the system. Network coordinated sum power optimization schemes for D2D communications underlaying uplink and downlink cellular spectrum is considered in this thesis. In particular, the system optimization target is to minimize the sum transmission power while guaranteeing the user specific rate constraints. Novel algorithms are proposed to solve the power minimization problem optimally. For the uplink, the problem is solved using joint transmit power control and receive beamforming algorithm. The downlink problem is reformulated as a second-order cone program (SOCP), and thus, it can be solved efficiently via standard SOCP solvers. Moreover, a decentralized algorithm is proposed that reduces the amount of control information exchange in comparison to the centralized approach. The performance of the proposed algorithms is compared with the conventional cellular scheme. Simulation results demonstrate that the proposed underlay D2D communication approach is capable of achieving significant performance gains over the conventional cellular scheme. Results also illustrate that the power consumption of the system is highly affected by the location of the interfering cellular user and whether the resources are shared in uplink or downlink. Therefore, four different resource sharing areas are defined for D2D communications. These areas specify the type of resources (i.e., downlink and uplink) suitable for D2D communication.

APA, Harvard, Vancouver, ISO, and other styles

48

Sheu, Hsin-Teng. "A coordinated decentralized flow and routing control algorithm for an automated highway system /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu148758564557836.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Kabir, Md Nayim. "Smart coordinated distribution system control to enable high level penetration of rooftop PVs." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/79956/1/MD%20Nayim_Kabir_Thesis.pdf.

Full text

Abstract:

This thesis addresses voltage violation problem, the most critical issue associated with high level penetration of photovoltaic (PV) in electricity distribution network. A coordinated control algorithm using the reactive power from PV inverter and integrated battery energy storage has been developed and investigated in different network scenarios in the thesis. Probable variations associated with solar generation, end-user participation and network parameters are also considered. Furthermore, a unified data model and well-defined communication protocol to ensure the smooth coordination between all the components during the operation of the algorithm is described. Finally this thesis incorporated the uncertainties of solar generation using probabilistic load flow analysis.

APA, Harvard, Vancouver, ISO, and other styles

50

Bird, John Paul. "Mixed Modes of Autonomy for Scalable Communication and Control of Multi-Robot Systems." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/29218.

Full text

Abstract:

Multi-robot systems (MRS) offer many performance benefits over single robots for tasks that can be completed by one robot. They offer potential redundancies to the system to improve robustness and allow tasks to be completed in parallel. These benefits, however, can be quickly offset by losses in productivity from diminishing returns caused by interference between robots and communication problems. This dissertation developed and evaluated MRS control architectures to solve the dynamic multi-robot autonomous routing problem. Dynamic multi-robot autonomous routing requires robots to complete a trip from their initial location at the time of task allocation to an assigned destination. The primary concern for the control architectures was how well the communication requirements and overall system performance scaled as the number of robots in the MRS got larger. The primary metrics for evaluation of the controller were the effective robot usage rate and the bandwidth usage. This dissertation evaluated several different approaches to solving dynamic multi-robot autonomous routing. The first three methods were based off of common MRS coordination approaches from previous research. These three control architectures with distributed control without communication (a swarm-like method), distributed control with communication, and centralized control. An additional architecture was developed to solve the problem in a way that scales better as the number of robots increase. This architecture, mixed mode autonomy, combines the strengths of distributed control with communication and centralized control. Like distributed control with communication, mixed mode autonomyâ s performance degrades gracefully with communication failures and is not dependent on a single controller. Like centralized control, there is oversight from a central controller to ensure repeatable high performance of the system. Each of the controllers other than distributed control without communication is based on building world models to facilitate coordination of the routes. A second variant of mixed mode autonomy was developed to allow robots to share parts of their world models with their peers when their models were incomplete or outdated. The system performance was evaluated for three example applications that represent different cases of dynamic multi-robot autonomous routing. These example applications were the automation of open pit mines, container terminals, and warehouses. The effective robot usage rates for mixed mode autonomy were generally significantly higher than the other controllers with a higher numbers of robots. The bandwidth usage was also much lower. These performance trends were also observed across a wide range of operating conditions for dynamic multi-robot autonomous routing. The original contributions from this work were the development of a new MRS control architecture, development of system model for the dynamic multi-robot autonomous routing problem, and identification of the tradeoffs for MRS design for the dynamic multi-robot autonomous routing problem.
Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Coordinated control'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles