95 research outputs found
Data-Driven Model-Free Adaptive Control of Z-Source Inverters
The universal paradigm shift towards green energy has accelerated the development of modern algorithms and technologies, among them converters such as Z-Source Inverters (ZSI) are playing an important role. ZSIs are single-stage inverters which are capable of performing both buck and boost operations through an impedance network that enables the shoot-through state. Despite all advantages, these inverters are associated with the non-minimum phase feature imposing heavy restrictions on their closed-loop response. Moreover, uncertainties such as parameter perturbation, unmodeled dynamics, and load disturbances may degrade their performance or even lead to instability, especially when model-based controllers are applied. To tackle these issues, a data-driven model-free adaptive controller is proposed in this paper which guarantees stability and the desired performance of the inverter in the presence of uncertainties. It performs the control action in two steps: First, a model of the system is updated using the current input and output signals of the system. Based on this updated model, the control action is re-tuned to achieve the desired performance. The convergence and stability of the proposed control system are proved in the Lyapunov sense. Experiments corroborate the effectiveness and superiority of the presented method over model-based controllers including PI, state feedback, and optimal robust linear quadratic integral controllers in terms of various metrics
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Non-Fragile Dissipative Fuzzy PID Control with Mixed Fading Measurements
Modelling, estimation and control of a twin-helicopter slung load transportation system
The development of a control system to transport and assemble cargo using two helicopters is presented in this thesis. It is more economical to use multiple lower cost helicopters in a coordinated manner to carry cargo than to use a single high performance helicopter for the transportation task. The reason for the generally higher cost of hiring high performance helicopters, is because they are not required often, and so, remain idle for most of their lifetime. Thus, using less specialised, lower performing helicopters to share the load is cheaper. Beyond just sharing the load of the cargo, the objective in this investigation is to control the attitude such that precise placement of the cargo can be made. This objective cannot be achieved using a single helicopter, unless a sophisticated tethering mechanism is developed. The installation of wind-turbine blades, powerline towers and radio masts in remote locations, are examples of where the application of this technology may be useful. The investigation of this thesis is around modelling, estimation and control of the twinhelicopter slung load transportation system. The title reflects the investigation that was required to be done to determine whether a scheme could be realisable. To test the concept, an experimental platform was developed. A small, light-weight and high performance avionics system was designed and interfaced to the helicopters. The experimentation was done indoors, and hence, the flying volume was limited. For the purpose of feedback and analysis, a motion capture system was developed to track the position and attitude of the helicopters. A high-fidelity mathematical model of a small-scale helicopter was developed. Estimation algorithms were then developed to optimally fuse the data from the instrumentation designed. The data was then used in a system identification exercise to find the parameters that capture the dynamics of the helicopter. The full constrained model of the twin-helicopter slung load dynamics was then developed. The high-fidelity multivariable, interacting system was then linearised to generate a set of uncertain plants. Unexpected resonant modes were investigated using modal analysis to understand their source. Robust controllers were designed using Quantitative Feedback Theory (QFT) for the individual helicopter attitude and altitude loops. A solution was found for the twin-helicopter load transportation system by decoupling the plant with a static pre-compensator and then designing a decentralised QFT controller for the 6 Ă 6 plant. The effort of this thesis is towards the (practical) realisation of a twin-helicopter aerial crane capable of attitude control; the architecture for the industrialisation of the twin-helicopter load transportation system is proposed
Observer based active fault tolerant control of descriptor systems
The active fault tolerant control (AFTC) uses the information provided by fault detection and fault diagnosis (FDD) or fault estimation (FE) systems offering an opportunity to improve the safety, reliability and survivability for complex modern systems. However, in the majority of the literature the roles of FDD/FE and reconfigurable control are described as separate design issues often using a standard state space (i.e. non-descriptor) system model approach. These separate FDD/FE and reconfigurable control designs may not achieve desired stability and robustness performance when combined within a closed-loop system.This work describes a new approach to the integration of FE and fault compensation as a form of AFTC within the context of a descriptor system rather than standard state space system. The proposed descriptor system approach has an integrated controller and observer design strategy offering better design flexibility compared with the equivalent approach using a standard state space system. An extended state observer (ESO) is developed to achieve state and fault estimation based on a joint linear matrix inequality (LMI) approach to pole-placement and Hâ optimization to minimize the effects of bounded exogenous disturbance and modelling uncertainty. A novel proportional derivative (PD)-ESO is introduced to achieve enhanced estimation performance, making use of the additional derivative gain. The proposed approaches are evaluated using a common numerical example adapted from the recent literature and the simulation results demonstrate clearly the feasibility and power of the integrated estimation and control AFTC strategy. The proposed AFTC design strategy is extended to an LPV descriptor system framework as a way of dealing with the robustness and stability of the system with bounded parameter variations arising from the non-linear system, where a numerical example demonstrates the feasibility of the use of the PD-ESO for FE and compensation integrated within the AFTC system.A non-linear offshore wind turbine benchmark system is studied as an application of the proposed design strategy. The proposed AFTC scheme uses the existing industry standard wind turbine generator angular speed reference control system as a âbaselineâ control within the AFTC scheme. The simulation results demonstrate the added value of the new AFTC system in terms of good fault tolerance properties, compared with the existing baseline system
Systems Structure and Control
The title of the book System, Structure and Control encompasses broad field of theory and applications of many different control approaches applied on different classes of dynamic systems. Output and state feedback control include among others robust control, optimal control or intelligent control methods such as fuzzy or neural network approach, dynamic systems are e.g. linear or nonlinear with or without time delay, fixed or uncertain, onedimensional or multidimensional. The applications cover all branches of human activities including any kind of industry, economics, biology, social sciences etc
Commande crone appliquée à l'optimisation de la production d'une éolienne
The research studies, in collaboration with VALEOL and IMS laboratory, propose several solutions to optimize the production and the efficiency of a wind turbine. The general theme of the work is based on control laws of the system or subsystems using the CRONE robust design. Each part highlights aspects of modeling, system identification and design before simulations or tests of scale and full size models. Chapter 1 provides an overview of the issues discussed in this manuscript, using states of the art and precisions on the industrial and economic context of 2013.Chapter 2 introduces the CRONE command for robust design. It is used to achieve the control of the rotation speed of a variable speed wind turbine, with an innovative architecture - mechanical variable speed solution and synchronous generator.Chapter 3 makes a comparison of three new optimization criteria for CRONE design. The aim is to reduce the methodology complexity and to facilitate handling by any user. The results are obtained through simulations on an academic example, then with a DFIG wind turbine model. Chapter 4 focuses on the reduction of structural loads transmitted by the wind on the turbine. It is about better control of the pitch angle by individual pitch control, depending on the rotor position or wind disturbances.Chapter 5 deals with the design of an anti-icing/de-icing system for blades. After the modeling and identification steps, the CRONE design is used to control the temperature of a heating coating disposed on the blades. An observer is finally designed to detect the presence of ice.Les Ă©tudes, menĂ©es en collaboration entre la sociĂ©tĂ© VALEOL et le laboratoire IMS, proposent des solutions pour optimiser la production et le fonctionnement d'une Ă©olienne. Il sâagit de travailler sur les lois de commande du systĂšme ou des sous-systĂšmes en utilisant la commande CRONE, rĂ©pondant Ă un besoin de robustesse. Chaque Ă©tude met en avant des aspects de modĂ©lisation, dâidentification et de synthĂšse de lois de commande avant mises en application au travers de simulations ou dâessais sur modĂšles rĂ©duits et taille rĂ©elle.Le chapitre 1 donne une vision dâensemble des problĂ©matiques traitĂ©es dans ce manuscrit, Ă lâaide dâĂ©tats de lâart et de remise dans le contexte Ă©conomique et industriel de 2013.Le chapitre 2 introduit la commande CRONE pour la synthĂšse de rĂ©gulateurs robustes. Cette mĂ©thodologie est utilisĂ©e pour rĂ©aliser lâasservissement de la vitesse de rotation dâune Ă©olienne Ă vitesse variable, prĂ©sentant une architecture innovante avec un variateur de vitesse mĂ©canique et gĂ©nĂ©ratrice synchrone.Le chapitre 3 Ă©tablit la comparaison de trois nouveaux critĂšres dâoptimisation pour la mĂ©thodologie CRONE. Le but est de rĂ©duire sa complexitĂ© et de faciliter sa manipulation par tout utilisateur. Les rĂ©sultats sur les diffĂ©rents critĂšres sont obtenus par simulations sur un exemple acadĂ©mique, puis sur un modĂšle dâĂ©olienne de type MADA.Le chapitre 4 porte sur la rĂ©duction des charges structurelles transmises par le vent Ă lâĂ©olienne. Il est question dâune amĂ©lioration du contrĂŽle de lâangle de pitch par action indĂ©pendante sur chaque pale en fonction de la position du rotor ou encore des perturbations liĂ©es au ventLe chapitre 5 est consacrĂ© Ă la conception dâun systĂšme dâantigivrage et dĂ©givrage dâune pale dans le cadre dâun projet Aquitain. AprĂšs modĂ©lisation et identification du procĂ©dĂ©, la commande CRONE est utilisĂ©e pour rĂ©guler la tempĂ©rature dâune peinture polymĂšre chauffante sous alimentation Ă©lectrique disposĂ©e sur les pales. LâĂ©tude est complĂ©tĂ©e par la mise en place dâun observateur pour la dĂ©tection de prĂ©sence de givre
Development of a vehicle dynamics controller for obstacle avoidance
As roads become busier and automotive technology improves, there is considerable potential for driver assistance systems to improve the safety of road users. Longitudinal collision warning and collision avoidance systems are starting to appear on production cars to assist drivers when required to stop in an emergency. Many luxury cars are also equipped with stability augmentation systems that prevent the car from spinning out of control during aggressive lateral manoeuvres. Combining these
concepts, there is a natural progression to systems that could assist in aiding or performing lateral collision avoidance manoeuvres.
A successful automatic lateral collision avoidance system would require convergent development of many fields of technology, from sensors and instrumentation to aid environmental awareness through to improvements in driver vehicle interfaces so that a degree of control can be smoothly and safely transferred between the driver and vehicle computer. A fundamental requirement of any
collision avoidance system is determination of a feasible path that avoids obstacles and a means of causing the vehicle to follow that trajectory.
This research focuses on feasible trajectory generation and
development of an automatic obstacle avoidance controller that integrates steering and braking action.
A controller is developed to cause a specially modified car (a Mercedes `S' class with steer-by-wire and brake-by-wire
capability) to perform an ISO 3888-2 emergency obstacle avoidance manoeuvre.
A nonlinear two-track vehicle model is developed and used to
derive optimal controller parameters using a series of simulations. Feedforward and feedback control is used to track a feasible reference trajectory. The feedforward control loops use inverse models of the vehicle dynamics. The feedback control loops are implemented as linear proportional controllers with a force allocation matrix used to apportion braking effort between redundant actuators.
Two trajectory generation routines are developed: a geometric method, for steering a vehicle at its physical limits; and an optimal method, which integrates steering and braking action to make full use of available traction. The optimal trajectory is obtained using a multi-stage convex optimisation procedure.
The overall controller performance is validated by simulation using a complex proprietary model of the vehicle that is reported to have been validated and calibrated against experimental data over several years of use in an industrial environment
ModÚles modulaires pour la simulation phénoménologique de circuits de broyage de minerais : mise en équations, calibrage des paramÚtres et étude de cas pour la commande
Face Ă la croissance du coĂ»t de lâĂ©nergie, la complexification des gisements, et une pression sociĂ©tale accrue pour rĂ©duire lâempreinte environnementale des activitĂ©s industrielles, lâindustrie miniĂšre est confrontĂ©e Ă un dĂ©fi de taille. Les usines minĂ©ralurgiques comptent pour une portion significative de la consommation Ă©nergĂ©tique des sites miniers alors que les circuits de broyage affichent une efficacitĂ© Ă©nergĂ©tique sous la barre des 30 %.LâamĂ©lioration de lâefficacitĂ© Ă©nergĂ©tique de lâĂ©tape de fragmentation apparait comme une avenue logique afin de diminuer lâempreinte Ă©nergĂ©tique des usines minĂ©ralurgiques. Cette recherche vise Ă dĂ©montrer que lâamĂ©lioration de la performance Ă©nergĂ©tique des circuits de comminution est possible en dĂ©finissant une stratĂ©gie dâopĂ©ration adaptĂ©e qui utilise de la rĂ©gulation avancĂ©e. Afin de rĂ©soudre la problĂ©matique, plusieurs Ă©chantillonnages de la rĂ©ponse dynamique du circuit de broyage de la mine Niobec ont Ă©tĂ© effectuĂ©s. La programmation et le calibrage dâun simulateur dynamique permettant de suivre la distribution granulomĂ©trique de chacun des flux du circuit de broyage de la mine ont Ă©tĂ© complĂ©tĂ©s par la suite. Ce simulateur a permis lâĂ©tude des performances du circuit dans diffĂ©rentes conditions dâopĂ©ration incluant lâintĂ©gration de perturbations dans le comportement du minerai. Une stratĂ©gie de rĂ©gulation avancĂ©e visant Ă maximiser la charge circulante du circuit a Ă©tĂ© dĂ©veloppĂ©e en utilisant des contrĂŽleurs PID. La maximisation de la charge circulante va de pair avec une amĂ©lioration de la classification dans le circuit et une diminution du surbroyage ce qui entraĂźne une amĂ©lioration de lâefficacitĂ© Ă©nergĂ©tique. En comparaison Ă la stratĂ©gie de contrĂŽle actuelle, celle proposĂ©e permet dâaugmenter le tonnage traitĂ© et de diminuer la consommation Ă©nergĂ©tique par tonne traitĂ©e. Les simulations montrent quâune rĂ©duction de 8,29 Ă 6,92 kWh par tonne traitĂ©e est envisageable. Cette amĂ©lioration de lâempreinte Ă©nergĂ©tique se fait de concert avec une augmentation de 155 Ă 184 tonnes traitĂ©es par heure tout en maintenant la cible de dimension du produit de broyage. La robustesse de la stratĂ©gie de rĂ©gulation proposĂ©e est dĂ©montrĂ©e par lâĂ©tude de sa rĂ©ponse Ă une variation de la duretĂ© du minerai traitĂ©. Ces rĂ©sultats montrent quâil est possible dâaccroitre significativement les performances en utilisant des stratĂ©gies de rĂ©gulation avancĂ©e Ă la portĂ©e des systĂšmes de contrĂŽle les plus communĂ©ment utilisĂ©s. Ils indiquent aussi que lâaugmentation de lâefficacitĂ© de la classification est un aspect important de lâamĂ©lioration des performances Ă©nergĂ©tiques
Technology for large space systems: A bibliography with indexes (supplement 17)
This bibliography lists 512 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1987 and June 30, 1987. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems
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