Tesi sul tema "Robust Control"
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1
Nakashima, Paulo Hiroaqui Ruiz. "Controle H2, H∞ e H2/H∞ aplicados a um robô manipulador subatuado". Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-08062017-122423/.
Testo completoAbstract (sommario):
Este trabalho apresenta os resultados da aplicação de três técnicas de controle utilizadas no projeto e implementação do controle de um manipulador subatuado planar de três juntas em série e de elos rígidos, projetado e construído pela Universidade Carnegie Mellon, EUA. Devido ao alto grau de não-linearidade deste sistema, seria muito difícil implementar um controlador H2, H∞ ou H2/H∞ que atuasse sozinho. Assim, propõe-se a utilização de um método de controle combinado: torque computado/H2, H∞ ou H2/H∞. No controle combinado, a porção correspondente ao torque computado lineariza e pré-compensa a dinâmica do modelo da planta nominal, enquanto a porção correspondente ao controle H2, H∞ ou H2/H∞ realiza uma pós-compensação dos erros residuais, que não foram completamente eliminados pelo método torque computado. Testes de acompanhamento de trajetória e testes de robustez são realizados aqui para comprovar a eficiência destes controladores, com resultados de implementação bastante satisfatórios.This work presents the application results of three control techniques used for the control design and implementation of a serial planar underactuated manipulator with three joints and rigid links, designed and built by the Carnegie Mellon University, USA. Due to the high non-linearity degree of this system, it would be very difficult to implement an H2, H∞ or H2/ H∞ control which would actuate on the system by itself. Therefore, it is proposed a combined control method: computed torque/ H2, H∞ or H2/H∞. In the combined control, the portion corresponding to the computed torque linearizes and pre-compensates the dynamics of the nominal model, while the portion corresponding to the H2, H∞ or H2/H∞ control realizes a pos-compensation of the residual errors, not completely removed by the computed torque method. Trajetory tracking and robustness tests are performed here to demonstrate the efficiency of these controllers, with very satisfatory implementation results.
2
Bekit, Biniam Weldai. "Robust nonlinear control of robot manipulators". Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321945.
Testo completo
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Löhning, Matthias [Verfasser]. "Robust Control of Elastic Robots / Matthias Löhning". München : Verlag Dr. Hut, 2011. http://d-nb.info/1015606512/34.
Testo completo
4
Cetinyurek, Aysun. "Robust Control Charts". Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12607987/index.pdf.
Testo completoAbstract (sommario):
ABSTRACT
ROBUST CONTROL CHARTS
Çetinyü
rek, Aysun M. Sc., Department of Statistics Supervisor: Dr. BariS Sü
rü
cü
Co-Supervisor: Assoc. Prof. Dr. Birdal Senoglu December 2006, 82 pages Control charts are one of the most commonly used tools in statistical process control. A prominent feature of the statistical process control is the Shewhart control chart that depends on the assumption of normality. However, violations of underlying normality assumption are common in practice. For this reason, control charts for symmetric distributions for both long- and short-tailed distributions are constructed by using least squares estimators and the robust estimators -modified maximum likelihood, trim, MAD and wave. In order to evaluate the performance of the charts under the assumed distribution and investigate robustness properties, the probability of plotting outside the control limits is calculated via Monte Carlo simulation technique.
5
Fu, Ye. "Robust adaptive control". Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/30574.
Testo completoAbstract (sommario):
This thesis describes discrete robust adaptive control methods based on using slow sampling and slow adaptation. For the stability analysis, we consider that the plant model order is not exactly known and assume that the estimation model order is lower than the plant model order. A stability condition is derived with a given upper limit for the adaptation gain which is related to a strictly positive real operator. Discussion of the relation between sampling and stability condition is then given. For the robust adaptive control design, we study slow adaptation and predictive control. For the slow adaptation, the main idea is to use only good estimates and use a compensation filter. Some frequency domain information on the plant is necessary for this method. For predictive control, we discuss the relationship between the extended control horizon and the critical sampling. For a simple case, it is shown that the larger extended control horizon brings more robust adaptive control.
The purpose of this thesis is to provide robust discrete adaptive controller design guidelines, especially in such cases as using slow sampling frequency, slow adaptation rate. It is true that in practice, for various discrete adaptive control algorithms, slow sampling and slow adaptation rate will bring more robustness. The use of slow sampling and slow adaptation rate is simple and economic, thus a careful choice of sampling rate and adaptation rate is highly recommended. This thesis provides such guidelines for choosing proper sampling rate and adaptation rate for robust discrete adaptive control.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
6
Shen, Dennis Ph D. Massachusetts Institute of Technology. "Robust synthetic control". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115743.
Testo completoAbstract (sommario):
Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 63-65).
In this thesis, we present a robust generalization of the synthetic control method. A distinguishing feature of our algorithm is that of de-noising the data matrix via singular value thresholding, which renders our approach robust in multiple facets: it automatically identifies a good subset of donors, functions without extraneous covariates (vital to existing methods), and overcomes missing data (never been addressed in prior works). To our knowledge, we provide the first theoretical finite sample analysis for a broader class of models than previously considered in literature. Additionally, we relate the inference quality of our estimator to the amount of training data available and show our estimator to be asymptotically consistent. In order to move beyond point estimates, we introduce a Bayesian framework that not only provides practitioners the ability to readily develop different estimators under various loss functions, but also equips them with the tools to quantitatively measure the uncertainty of their model/estimates through posterior probabilities. Our empirical results demonstrate that our robust generalization yields a positive impact over the classical synthetic control method, underscoring the value of our key de-noising procedure.
by Dennis Shen.
S.M.
7
Liu, Chengyuan. "Robust model predictive control : robust control invariant sets and efficient implementation". Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/45529.
Testo completoAbstract (sommario):
Robust model predictive control (RMPC) is widely used in industry. However, the online computational burden of this algorithm restricts its development and application to systems with relatively slow dynamics. We investigate this problem in this thesis with the overall aim of reducing the online computational burden and improving the online efficiency. In RMPC schemes, robust control invariant (RCI) sets are vitally important in dealing with constraints and providing stability. They can be used as terminal (invariant) sets in RMPC schemes to reduce the online computational burden and ensure stability simultaneously. To this end, we present a novel algorithm for the computation of full-complexity polytopic RCI sets, and the corresponding feedback control law, for linear discrete-time systems subject to output and initial state constraints, performance bounds, and bounded additive disturbances. Two types of uncertainty, structured norm-bounded and polytopic uncertainty, are considered. These algorithms are then extended to deal with systems subject to asymmetric initial state and output constraints. Furthermore, the concept of RCI sets can be extended to invariant tubes, which are fundamental elements in tube based RMPC scheme. The online computational burden of tube based RMPC schemes is largely reduced to the same level as model predictive control for nominal systems. However, it is important that the constraint tightening that is needed is not excessive, otherwise the performance of the MPC design may deteriorate, and there may even not exist a feasible control law. Here, the algorithms we proposed for RCI set approximations are extended and applied to the problem of reducing the constraint tightening in tube based RMPC schemes. In order to ameliorate the computational complexity of the online RMPC algorithms, we propose an online-offline RMPC method, where a causal state feedback structure on the controller is considered. In order to improve the efficiency of the online computation, we calculate the state feedback gain offline using a semi-definite program (SDP). Then we propose a novel method to compute the control perturbation component online. The online optimization problem is derived using Farkas' Theorem, and then approximated by a quadratic program (QP) to reduce the online computational burden. A further approximation is made to derive a simplified online optimization problem, which results in a large reduction in the number of variables. Numerical examples are provided that demonstrate the advantages of all our proposed algorithms over current schemes.
8
Nguyen, Quan T. "Robust and Adaptive Dynamic Walking of Bipedal Robots". Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1102.
Testo completoAbstract (sommario):
Legged locomotion has several interesting challenges that need to be addressed, such as the ability of dynamically walk over rough terrain like stairs or stepping stones, as well as the ability to adapt to unexpected changes in the environment and the dynamic model of the robot. This thesis is driven towards solving these challenges and makes contributions on theoretical and experimental aspects to address: dynamic walking, model uncertainty, and rough terrain. On the theoretical front, we introduce and develop a unified robust and adaptive control framework that enables the ability to enforce stability and safety-critical constraints arising from robotic motion tasks under a high level of model uncertainty. We also present a novel method of walking gait optimization and gait library to address the challenge of dynamic robotic walking over stochastically generated stepping stones with significant variations in step length and step height, and where the robot has knowledge about the location of the next discrete foothold only one step ahead. On the experimental front, our proposed methods are successfully validated on ATRIAS, an underactuated, human-scale bipedal robot. In particular, experimental demonstrations illustrate our controller being able to dynamically walk at 0.6 m/s over terrain with step length variation of 23 to 78 cm, as well as simultaneous variation in step length and step height of 35 to 60cm and -22 to 22cm respectively. In addition to that, we also successfully implemented our proposed adaptive controller on the robot, which enables the ability to carry an unknown load up to 68 lb (31 kg) while maintaining very small tracking errors of about 0.01 deg (0.0017 rad) at all joints. To be more specific, we firstly develop robust control Lyapunov function based quadratic program (CLFQP) controller and L1 adaptive control to handle model uncertainty for bipedal robots. An application is dynamic walking while carrying an unknown load. The robust CLF-QP controller can guarantee robustness via a quadratic program that can be extended further to achieve robust safety-critical control. The L1 adaptive control can estimate and adapt to the presence of model uncertainty in the system dynamics. We then present a novel methodology to achieve dynamic walking for underactuated and hybrid dynamcal bipedal robots subject to safety-critical constraints. The proposed controller is based on the combination of control Barrier functions (CBFs) and control Lyapunov functions (CLFs) implemented as a state-based online quadratic program to achieve stability under input and state constraints. The main contribution of this work is the control design to enable stable dynamical bipedal walking subject to strict safety constraints that arise due to walking over a terrain with randomly generated discrete footholds. We next introduce Exponential Control Barrier Functions (ECBFs) as means to enforce high relativedegree safety constraints for nonlinear systems. We also develop a systematic design method that enables creating the Exponential CBFs for nonlinear systems making use of tools from linear control theory. Our method creates a smooth boundary for the safety set via an exponential function, therefore is called Exponential CBFs. Similar to exponential stability and linear control, the exponential boundary of our proposed method helps to have smoother control inputs and guarantee the robustness under model uncertainty. The proposed control design is numerically validated on a relative degree 4 nonlinear system (the two-link pendulum with elastic actuators and experimentally validated on a relative degree 6 linear system (the serial cart-spring system). Thanks to these advantages of Exponential CBFs, we then can apply the method to the problem of 3D dynamic walking with varied step length and step width as well as dynamic walking on time-varying stepping stones. For the work of using CBF for stepping stones, we use only one nominal walking gait. Therefore the range of step length variation is limited ([25 : 60](cm)). In order to improve the performance, we incorporate CBF with gait library and increase the step length range significantly ([10 : 100](cm)). While handling physical constraints and step transition via CBFs appears to work well, these constraints often become active at step switching. In order to resolve this issue, we introduce the approach of 2-step periodic walking. This method not only gives better step transitions but also offers a solution for the problem of changing both step length and step height. Experimental validation on the real robot was also successful for the problem of dynamic walking on stepping stones with step lengths varied within [23 : 78](cm) and average walking speed of 0:6(m=s). In order to address the problems of robust control and safety-critical control in a unified control framework, we present a novel method of optimal robust control through a quadratic program that offers tracking stability while subject to input and state-based constraints as well as safety-critical constraints for nonlinear dynamical robotic systems under significant model uncertainty. The proposed method formulates robust control Lyapunov and barrier functions to provide guarantees of stability and safety in the presence of model uncertainty. We evaluate our proposed control design on different applications ranging from a single-link pendulum to dynamic walking of bipedal robot subject to contact force constraints as well as safety-critical precise foot placements on stepping stones, all while subject to significant model uncertainty. We conduct preliminary experimental validation of the proposed controller on a rectilinear spring-cart system under different types of model uncertainty and perturbations. To solve this problem, we also present another solution of adaptive CBF-CLF controller, that enables the ability to adapt to the effect of model uncertainty to maintain both stability and safety. In comparison with the robust CBF-CLF controller, this method not only can handle a higher level of model uncertainty but is also less aggressive if there is no model uncertainty presented in the system.
9
Yu, Hongnian. "Modelling and robust adaptive control of robot manipulators". Thesis, King's College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720361.
Testo completo
10
Yoon, Tae-Woong. "Robust adaptive predictive control". Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359527.
Testo completo
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Owens, T. J. "Robust control system design]". Thesis, University of Strathclyde, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381724.
Testo completo
12
Thamotheram, Craig P. "Essays in robust control". Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/66994/.
Testo completoAbstract (sommario):
My thesis consists of three chapters on issues related to the macroeconomic literature of robust control. I detail the salient properties of a RBC model with robust preferences and stochastic-volatility in technological growth. Using this as a framework, I study how to numerically approximate the worst case distribution and how agents check to see whether or not the misspecifications they consider are reasonable. This literature allows for agents to distrust the underlying statistical model governing the economy and seek policies that are ’robust’ to this model misspecification. This is accomplished in the context of a fictitious two player dynamic game between an optimising agent and her “evil” alter ego who is attempting to distort the underlying probability distribution to push the agent into unfavourable regions. The evil agent is constrained to the extent that she can distort the distribution by a parameter on the relative entropy (Kullback-Leibler divergence) between her chosen distortion and the underlying probability distribution. This parameter is somewhat arbitrary and the literature proposes a simple log-likelihood ratio test to pin it down by placing restrictions on the ability of the agent to statistically distinguish between the time series generated under the approximating and distorted model. The solution to the “evil” agents distorted distribution has no known closed form in the non-linear non-Gaussian model used but can be approximated with perturbation methods. Standard Monte Carlo methods then allow the distribution to be sampled from. The first chapter constitutes an introduction to the model used as the base unit for economic analysis in the following chapters. It introduces robustness as a concept to incorporate aversion to model misspecification. Details a very simple RBC model with the addition of stochastic volatility in technology and presents its solution methodology. Finally, the economic dynamics of the model are tested in order to validate that the model is reasonable representation of the macroeconomy and does indeed have interesting non-linearities, as well as that the non-Guassianity introduced by stochastic volatility is economically significant. This is done by considering the models moments and impulse response functions to volatility shocks. The second chapter explores the trade-offs involved in approximating and drawing from the worst case distribution using perturbation methods, a novel method using a simple completing the square argument and two Monte Carlo techniques, importance sampling and MCMC. Naturally, these techniques engender a certain degree of Monte Carlo variation in the resulting approximations. I explore the accuracy of these approximations using summary statistics and ? inaccuracy, a measure of distance between two distributions. Linear and Gaussian models of robust control allow for a analytic solution of the worst case distribution that remains Gaussian. I use this as guidance to check if a simple translated and spread Gaussian distribution approximates the worst case distribution to a similar level of accuracy as that recorded for the Monte Carlo methods. Additionally, I apply the formal empirical test of the finiteness of the variance of the importance sampling weights of ? to check the validity of using IS. This chapter serves as a practical guide for those wishing to apply these techniques as to the trade-offs involved with the various methods. The third chapter explores the statistical distinguishability between the two time series using sequential Monte Carlo methods, namely the particle filter, to evaluate the likelihoods. In comparison to the majority of the literature on robust control, the likelihoods that result from the non-linear and non-Gaussian model studied are non-analytic. Thus, the evaluation of their likelihood introduces a second source of variation in the calculation of detection error. I design a simple yet novel approach that explicitly acknowledges this in the calculation of the detection error. In order to choose the parameters for this new approach I present Monte Carlo evidence on the base unit of its construction. Also, I explore the properties of DEP across three dimensions. First, I test to see if DEP varies across the state space as well. In order to do this, and give the best chance for a difference to be found, I calculate the DEP conditional upon a given initial state. Second, for differing values of the robustness parameter I calculate the DEP in the spirit of ?, where the simulated series are generated from the unconditional distribution and the particle filter for each model also takes its initial state values from their respective unconditional distributions. Finally, for a given value of the robustness parameter I test to see if the simulation method for the worst case distribution affects the evolution of DEP, testing perturbation versus completing the square.
13
Fahmy, Sherif Farid Fahmy. "Nonlinear robust H∞ control". Thesis, University of Sheffield, 2006. http://etheses.whiterose.ac.uk/14887/.
Testo completoAbstract (sommario):
A new theory is proposed for the full-information finite and infinite horizontime robust H∞ control that is equivalently effective for the regulation and/or tracking problems of the general class of time-varying nonlinear systems under the presence of exogenous disturbance inputs. The theory employs the sequence of linear-quadratic and time-varying approximations, that were recently introduced in the optimal control framework, to transform the nonlinear H∞ control problem into a sequence of linearquadratic robust H∞ control problems by using well-known results from the existing Riccati-based theory of the maturing classical linear robust control. The proposed method, as in the optimal control case, requires solving an approximating sequence of Riccati equations (ASRE), to find linear time-varying feedback controllers for such disturbed nonlinear systems while employing classical methods. Under very mild conditions of local Lipschitz continuity, these iterative sequences of solutions are known to converge to the unique viscosity solution of the Hamilton-lacobi-Bellman partial differential equation of the original nonlinear optimal control problem in the weak form (Cimen, 2003); and should hold for the robust control problems herein. The theory is analytically illustrated by directly applying it to some sophisticated nonlinear dynamical models of practical real-world applications. Under a r -iteration sense, such a theory gives the control engineer and designer more transparent control requirements to be incorporated a priori to fine-tune between robustness and optimality needs. It is believed, however, that the automatic state-regulation robust ASRE feedback control systems and techniques provided in this thesis yield very effective control actions in theory, in view of its computational simplicity and its validation by means of classical numerical techniques, and can straightforwardly be implemented in practice as the feedback controller is constrained to be linear with respect to its inputs.
14
Kale, Mangesh M. "Robust reconfigurable flight control". Thesis, University of Southampton, 2004. https://eprints.soton.ac.uk/45932/.
Testo completoAbstract (sommario):
From the perspective control practitioners, control of dynamics systems subjected to varying parameters is not a new topic. However systematic methods to accommodate such problems are relatively few and recent. This thesis addresses a subset of such problems falling under the nomenclature of Reconfigurable Control Systems in relation to flight control applications. A survey in the initial phase of research indicated a wide range of ad-hoc solutions with relatively brittle or non-existent theoretical guarantees towards to the stability of the entire system. Often the reconfigurable architecture consists of multiple conceptual components performing task of identifying system parameter changes, monitoring degradation in system performance and eventually finding some corrective action to regain lost performance. The change in system parameters if attributed to faults and damages to system, then the task of the control system is to achieve fault tolerance. Such fault tolerance is of high interest for flight control community since such a control system adaptation may lead to accommodation of real life faults during aircraft operation such as control surface damages, hydraulic actuation failures etc. The thesis work aims towards developing online control redesign methods capable of taking into account realistic requirements. The goals are 1) To find control input values in presence of faults. 2) Accommodate changes in performance criterion in presence of faults and, 3) Incorporate actuator limitations such as rate and position bounds. The research work is divided in three subparts. The initial phase consists of a study of existing solutions and methods capable of providing reconfigurable flight control architectures. This phase also covers some flight control literature relevant in the context of faults. Though the conclusions of this initial phase seem theoretically simple and straight forward, it is interesting to understand the amount of time and efforts invested by real world flight control practitioners to deduce these results. Essentially the work flow of this research work stems from practical requirement eventually leading to theoretical developments that can approximate the requirements often demanded by the people in field. The second phase consists of study and application of existing Model Predictive Control methods to the field of reconfigurable flight control. MPC has been successful in major complex control problems due to its online constrained optimisation methodology. Along-with certain theoretical extensions it is well capable of providing a successful means to redesign control action online in presence of failures. Simulation studies of sufficient fidelity and complexity on a full envelop fighter aircraft nonlinear model prove such control reconfiguration capabilities of MPC. Some new extensions of MPC have been developed to show it performing in a superior manner to conventional nominal formulations. The third phase of the research work focuses on further theoretical developments in the field robust adaptive control in MPC frame of operation. A new MPC formulation is derived which can accommodate constraints, uncertainty and constant disturbances (due to failed inputs). The novelty lies in the theoretical properties of this MPC as under certain conditions it is guaranteed to be asymptotically stable. This setup implements an optimization problem more complex than that of the nominal case. Typically, when disturbances and uncertainties are incorporated into the performance measure within MPC formulations, mini-max (worst-case) NP-hard problems can arise. The thesis contributes to the theory of robust synthesis by proposing a convex relaxation of a mini-max based MPC controller by adopting a Linear Matrix Inequality (LMI) optimisation formulation.
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Schaich, Rainer Manuel. "Robust model predictive control". Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:94e75a62-a801-47e1-8cb8-668e8309d477.
Testo completoAbstract (sommario):
This thesis deals with the topic of min-max formulations of robust model predictive control problems. The sets involved in guaranteeing robust feasibility of the min-max program in the presence of state constraints are of particular interest, and expanding the applicability of well understood solvers of linearly constrained quadratic min-max programs is the main focus. To this end, a generalisation for the set of uncertainty is considered: instead of fixed bounds on the uncertainty, state- and input-dependent bounds are used. To deal with state- and input dependent constraint sets a framework for a particular class of set-valued maps is utilised, namely parametrically convex set-valued maps. Relevant properties and operations are developed to accommodate parametrically convex set-valued maps in the context of robust model predictive control. A quintessential part of this work is the study of fundamental properties of piecewise polyhedral set-valued maps which are parametrically convex, we show that one particular property is that their combinatorial structure is constant. The study of polytopic maps with a rigid combinatorial structure allows the use of an optimisation based approach of robustifying constrained control problems with probabilistic constraints. Auxiliary polytopic constraint sets, used to replace probabilistic constraints by deterministic ones, can be optimised to minimise the conservatism introduced while guaranteeing constraint satisfaction of the original probabilistic constraint. We furthermore study the behaviour of the maximal robust positive invariant set for the case of scaled uncertainty and show that this set is continuously polytopic up to a critical scaling factor, which we can approximate a-priori with an arbitrary degree of accuracy. Relevant theoretical statements are developed, discussed and illustrated with examples.
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Manesco, Rodolpho Moreira [UNESP]. "Projeto de controladores robustos para sistemas sujeitos a falhas estruturais usando realimentação estática de saída". Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/87072.
Testo completoAbstract (sommario):
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manesco_rm_me_ilha.pdf: 1114845 bytes, checksum: 86414a871a4a2dd233af7709965f2bb3 (MD5)Este trabalho trata do problema de estabilização robusta e de novas técnicas de otimização robusta de sistemas lineares contínuos no tempo sujeitos a incertezas politópicas no modelo. Todo trabalho é fundamentado em leis de controle por realimentação estática de saída. As técnicas de projetos apresentam condições suficientes na forma de desigualdades matriciais lineares (LMIs, acrônimo inglês para Linear Matrix Inequalities), formuladas com base na teoria de estabilidade segundo Lyapunov. Além do mais, índices de desempenho como a taxa de decaimento também são considerados no modelo, visto que, garantir apenas a estabilidade nem sempre é suficiente para fins de engenharia. As modelagens LMIs são realizadas através de lemas largamente utilizados em diversas áreas de sistema de controle, como, por exemplo, o lema de Finsler, que permite o uso tanto de uma função de Lyapunov dependente de parâmetros (PDLF, acrônimo inglês para Parameter-Dependent Lyapunov Function) quanto o uso de LMIs clássicas baseadas na existência de uma função de Lyapunov quadrática comum (CQLF, acrônimo inglês para Common Quadratic Lyapunov Function) para assegurar a estabilidade assintótica dos sistemas. Comparações entre ambos os métodos de projeto foram realizadas, e o presente trabalho apresenta resultados menos conservadores na maior parte das ocasiões, isto é, na maioria das vezes os problemas podem ser solucionados com PDLFs e não com CQLFs. Ainda, é proposta neste trabalho uma nova técnica para otimização da norma de controladores de saída e comparações são realizadas entre os métodos como forma de verificar a sua eficácia. O desafio deste trabalho consiste em realizar projetos de controladores robustos via LMIs através da realimentação estática de saída que fossem passíveis de implementação...
This thesis addresses the problem of robust stabilization and robust new optimization techniques for continuous-time linear systems subject to polytopic uncertainties in the model. All work is based on static output feedback control laws. The text presents sufficient conditions for control projects in the form of Linear Matrix Inequalities (LMIs), formulated in terms of the Lyapunov stability theory. Moreover, performance indices as decay rate are also considered in the model, since only ensure stability is not always sufficient for engineering purposes. The modeling is performed using LMIs widely used lemmas in several areas of control systems , such as, for example, the Lemma of Finsler, which allows the use of Parameters Dependent Lyapunov Functions (PDLFs) as the use of classic LMIs based on the existence of a Common Quadratic Lyapunov Functions (CQLFs) to ensure asymptotic stability of the systems. Comparisons between the two design methods were performed, and the present work shows less conservative results on most occasions, in other words, the problems can be solved with PDLFs and not with CQLFs in most cases. Still, this work proposes a new technique for optimizing the norm of output controllers and comparisons are made between the methods as a way to verify its effectiveness. The challenge of this work was to carry out robust controllers designs based on LMIs through static output feedback that could be implemented on a real physical system subject to failure. Thus, simulations were made and the designed output controllers were implemented in a 3-DOF (Degrees Of Freedom) helicopter bench of Quanserr trademark, always seeking alternative controllers with better performance and lower norm that... (Complete abstract click electronic access below)
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Silva, João Henrique Pereira [UNESP]. "Controle robusto h-infinito chaveado para sistemas lineares". Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/87077.
Testo completoAbstract (sommario):
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silva_jhp_me_ilha.pdf: 1343237 bytes, checksum: 23b5f5f368f8d9c7eb211e7c5d1826a7 (MD5)Neste trabalho são propostas condições suficientes para o controle H∞ chaveado de sistemas lineares incertos contínuos no tempo. A técnica abordada para este estudo consiste na utilização de uma função quadrática de Lyapunov e em um caso mais específico, uma função quadrática de Lyapunov por partes. A análise de estabilidade é descrita por meio de Desigualdades Matriciais Lineares (em inglês: Linear Matrix Inequalities), LMIs, que, quando factíveis, são facilmente resolvidas por meio de ferramentas disponíveis na literatura de programação convexa. Assim é apresentada uma metodologia de chaveamento do ganho de realimentação do vetor de estado, que assegura também o critério de desempenho H∞, cuja estratégia busca a obtenção do mínimo valor da derivada de uma função de Lyapunov quadrática. O método foi estendido com o emprego de uma função de Lyapunov quadrática por partes, cujo projeto é baseado nas desigualdades de Lyapunov-Metzler. É demonstrado que esta nova estratégia de chaveamento, além de uma implementação simples, oferece uma flexibilização das LMIs em comparação com os métodos convencionais que também utilizam o controle H∞. A teoria é ilustrada através de exemplos, que permitem comprovar o bom desempenho dos métodos propostos, incluindo a implementação em laboratório do controle de um helicóptero 3-DOF de bancada da QUANSER, sujeito a falhas estruturais.
Sufficient conditions for the switched H∞ control of continuous-time uncertain linear systems are proposed. The technique discussed in this study is based on quadratic Lyapunov functions and a piecewise quadratic Lyapunov functions. The stability analysis is described by LMIs that, when feasible, are easily solved by available tools in the convex programming literature. Thus, a methodology for designing the switching of state vector feedback gains, which also ensures H∞ performance criterion, is presented. This new procedure chooses the state feedback gain that returns the minimum value of the time derivative of the Lyapunov function. The method was extended to a piecewise quadratic Lyapunov function and is designed from the solution of Lyapunov-Metzler inequalities. It is shown that this switching strategy, beyond a simple implementation, offers a relaxation in the LMIs, when compared with the conventional methods used in H∞ control. The procedure are illustrated by means of examples, including an implementation in the control of a 3-DOF helicopter, subject to structural failures.
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Buzachero, Luiz Francisco Sanches [UNESP]. "Controle robusto chaveado de sistemas lineares variantes no tempo com aplicação em falhas estruturais". Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/110512.
Testo completoAbstract (sommario):
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000794484.pdf: 4606369 bytes, checksum: 3b03f3088fb54f098f7565bc5b9ad8da (MD5)Nesta tese apresentam-se resultados para a estabilidade robusta de sistemas lineares sujeitos a incertezas paramétricas do tipo politópicas, variantes no tempo (do inglês Linear Parameter Varying - LPV). De início, expõe-se um método aprimorado para o projeto com otimização da norma de controladores robustos via desigualdades matriciais lineares (do inglês Linear Matrix Inequalitites - LMIs), com base na teoria de estabilidade segundo Lyapunov. Esta nova formulação foi manipulada utilizando o lema de Finsler, e permitiu encontrar melhores resultados de factibilidade com o acréscimo de matrizes extras e redução do número de LMIs. Neste novo equacionamento houve a inclusão do índice de desempenho da taxa de decaimento, responsável por diminuir o tempo de duração do período transitório, e também da otimização da norma dos controladores, responsável por menores ganhos mantendo a mesma eficiência dos requisitos de projeto. Devido a importantes resultados da literatura para o projeto de controladores robustos com incertezas variantes no tempo, optou-se por explorar o projeto de controladores dinâmicos chaveados, inovando-se no tocante ao acréscimo da taxa de decaimento e à otimização da norma dos controladores chaveados, o que possibilitou encontrar melhores resultados de implementação. Por fim, foram propostos critérios menos conservadores para a análise de estabilidade e projeto de controladores chaveados, utilizando funções de Lyapunov quadráticas por partes do tipo mínimo. A vantagem desse procedimento está no aumento dos parâmetros de relaxação porém, concebido através de formulações baseadas em desigualdades matriciais bilineares (do inglês Bilinear Matrix Inequalitites - BMIs), nos quais os termos e se encontram no produto entre variáveis escalares de otimização e matrizes, que também são variáveis do procedimento de otimização. Apresentam-se, no corpo do texto, exemplos numéricos e ...
This thesis presents results for robust stability of linear systems subject to polytopic timevarying parametric uncertainties (LPV). To start with, an improved method for the optimal gain design of robust controllers via Linear Matrix Inequalities (LMI), based on Lyapunov stability theory is presented. This new formulation was manipulated using the Finsler lemma, which enabled finding better feasibility results with the addition of extra matrices and reducing the number of LMIs. In this new equation it was included the decay rate performance index, responsible for reducing the transitional period time, as well as the controllers norm optimization, responsible for lower gains while maintaining the same project requirements efficiency. Then, due to important results in literature regarding the design of robust controllers with time-varying uncertainties, the design of switched dynamic controllers was explored by including the decay rate index and the optimization of the switched controllers norm in the equation, which allowed finding better implementation results. Finally, less conservative criteria were proposed for stability analysis and design of switched controllers using minimum-type piecewise quadratic Lyapunov functions. The advantage of this procedure lies in the increase of relaxation parameters, however, designed through formulations based on Bilinear Matrix Inequalities (BMIs), where the bilinear terms are in the product between optimization scalar variables and matrices, which are also variables on the optimization procedure. Numerical examples are presented and simulated to illustrate the efficiency of the proposed methodologies in relation to other existing throughout the text. The designed controllers were implemented using these new proposals in a Three Degrees Of Freedom (3-DOF) helicopter or in the Shake Table II (STII) + Active Mass Dumper - One Floor (AMD-1) system, in order to validate in practice the proposed theories
19
Manesco, Rodolpho Moreira. "Projeto de controladores robustos para sistemas sujeitos a falhas estruturais usando realimentação estática de saída /". Ilha Solteira, 2013. http://hdl.handle.net/11449/87072.
Testo completoAbstract (sommario):
Orientador: Edvaldo AssunçãoBanca: Marcelo Carvalho Minhoto Teixeira
Banca: Ricardo Coração de Leão Fontoura de Oliveira
Resumo: Este trabalho trata do problema de estabilização robusta e de novas técnicas de otimização robusta de sistemas lineares contínuos no tempo sujeitos a incertezas politópicas no modelo. Todo trabalho é fundamentado em leis de controle por realimentação estática de saída. As técnicas de projetos apresentam condições suficientes na forma de desigualdades matriciais lineares (LMIs, acrônimo inglês para Linear Matrix Inequalities), formuladas com base na teoria de estabilidade segundo Lyapunov. Além do mais, índices de desempenho como a taxa de decaimento também são considerados no modelo, visto que, garantir apenas a estabilidade nem sempre é suficiente para fins de engenharia. As modelagens LMIs são realizadas através de lemas largamente utilizados em diversas áreas de sistema de controle, como, por exemplo, o lema de Finsler, que permite o uso tanto de uma função de Lyapunov dependente de parâmetros (PDLF, acrônimo inglês para Parameter-Dependent Lyapunov Function) quanto o uso de LMIs clássicas baseadas na existência de uma função de Lyapunov quadrática comum (CQLF, acrônimo inglês para Common Quadratic Lyapunov Function) para assegurar a estabilidade assintótica dos sistemas. Comparações entre ambos os métodos de projeto foram realizadas, e o presente trabalho apresenta resultados menos conservadores na maior parte das ocasiões, isto é, na maioria das vezes os problemas podem ser solucionados com PDLFs e não com CQLFs. Ainda, é proposta neste trabalho uma nova técnica para otimização da norma de controladores de saída e comparações são realizadas entre os métodos como forma de verificar a sua eficácia. O desafio deste trabalho consiste em realizar projetos de controladores robustos via LMIs através da realimentação estática de saída que fossem passíveis de implementação... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This thesis addresses the problem of robust stabilization and robust new optimization techniques for continuous-time linear systems subject to polytopic uncertainties in the model. All work is based on static output feedback control laws. The text presents sufficient conditions for control projects in the form of Linear Matrix Inequalities (LMIs), formulated in terms of the Lyapunov stability theory. Moreover, performance indices as decay rate are also considered in the model, since only ensure stability is not always sufficient for engineering purposes. The modeling is performed using LMIs widely used lemmas in several areas of control systems , such as, for example, the Lemma of Finsler, which allows the use of Parameters Dependent Lyapunov Functions (PDLFs) as the use of classic LMIs based on the existence of a Common Quadratic Lyapunov Functions (CQLFs) to ensure asymptotic stability of the systems. Comparisons between the two design methods were performed, and the present work shows less conservative results on most occasions, in other words, the problems can be solved with PDLFs and not with CQLFs in most cases. Still, this work proposes a new technique for optimizing the norm of output controllers and comparisons are made between the methods as a way to verify its effectiveness. The challenge of this work was to carry out robust controllers designs based on LMIs through static output feedback that could be implemented on a real physical system subject to failure. Thus, simulations were made and the designed output controllers were implemented in a 3-DOF (Degrees Of Freedom) helicopter bench of Quanserr trademark, always seeking alternative controllers with better performance and lower norm that... (Complete abstract click electronic access below)
Mestre
20
Silva, João Henrique Pereira. "Controle robusto h-infinito chaveado para sistemas lineares /". Ilha Solteira, 2013. http://hdl.handle.net/11449/87077.
Testo completoAbstract (sommario):
Orientador: Marcelo Carvalho Minhoto TeixeiraBanca: Edvaldo Assunção
Banca: Márcio Roberto Covacic.
Resumo: Neste trabalho são propostas condições suficientes para o controle H∞ chaveado de sistemas lineares incertos contínuos no tempo. A técnica abordada para este estudo consiste na utilização de uma função quadrática de Lyapunov e em um caso mais específico, uma função quadrática de Lyapunov por partes. A análise de estabilidade é descrita por meio de Desigualdades Matriciais Lineares (em inglês: Linear Matrix Inequalities), LMIs, que, quando factíveis, são facilmente resolvidas por meio de ferramentas disponíveis na literatura de programação convexa. Assim é apresentada uma metodologia de chaveamento do ganho de realimentação do vetor de estado, que assegura também o critério de desempenho H∞, cuja estratégia busca a obtenção do mínimo valor da derivada de uma função de Lyapunov quadrática. O método foi estendido com o emprego de uma função de Lyapunov quadrática por partes, cujo projeto é baseado nas desigualdades de Lyapunov-Metzler. É demonstrado que esta nova estratégia de chaveamento, além de uma implementação simples, oferece uma flexibilização das LMIs em comparação com os métodos convencionais que também utilizam o controle H∞. A teoria é ilustrada através de exemplos, que permitem comprovar o bom desempenho dos métodos propostos, incluindo a implementação em laboratório do controle de um helicóptero 3-DOF de bancada da QUANSER, sujeito a falhas estruturais.
Abstract: Sufficient conditions for the switched H∞ control of continuous-time uncertain linear systems are proposed. The technique discussed in this study is based on quadratic Lyapunov functions and a piecewise quadratic Lyapunov functions. The stability analysis is described by LMIs that, when feasible, are easily solved by available tools in the convex programming literature. Thus, a methodology for designing the switching of state vector feedback gains, which also ensures H∞ performance criterion, is presented. This new procedure chooses the state feedback gain that returns the minimum value of the time derivative of the Lyapunov function. The method was extended to a piecewise quadratic Lyapunov function and is designed from the solution of Lyapunov-Metzler inequalities. It is shown that this switching strategy, beyond a simple implementation, offers a relaxation in the LMIs, when compared with the conventional methods used in H∞ control. The procedure are illustrated by means of examples, including an implementation in the control of a 3-DOF helicopter, subject to structural failures.
Mestre
21
Buzachero, Luiz Francisco Sanches. "Controle robusto chaveado de sistemas lineares variantes no tempo com aplicação em falhas estruturais /". Ilha Solteira, 2014. http://hdl.handle.net/11449/110512.
Testo completoAbstract (sommario):
Orientador: Edvaldo AssunçãoBanca: Marcelo Carvalho Minhoto Teixeira
Banca: Rodrigo Cardim
Banca: Marcio Roberto Covacic
Banca: Eduardo Fontoura Costa
Resumo: Nesta tese apresentam-se resultados para a estabilidade robusta de sistemas lineares sujeitos a incertezas paramétricas do tipo politópicas, variantes no tempo (do inglês Linear Parameter Varying - LPV). De início, expõe-se um método aprimorado para o projeto com otimização da norma de controladores robustos via desigualdades matriciais lineares (do inglês Linear Matrix Inequalitites - LMIs), com base na teoria de estabilidade segundo Lyapunov. Esta nova formulação foi manipulada utilizando o lema de Finsler, e permitiu encontrar melhores resultados de factibilidade com o acréscimo de matrizes extras e redução do número de LMIs. Neste novo equacionamento houve a inclusão do índice de desempenho da taxa de decaimento, responsável por diminuir o tempo de duração do período transitório, e também da otimização da norma dos controladores, responsável por menores ganhos mantendo a mesma eficiência dos requisitos de projeto. Devido a importantes resultados da literatura para o projeto de controladores robustos com incertezas variantes no tempo, optou-se por explorar o projeto de controladores dinâmicos chaveados, inovando-se no tocante ao acréscimo da taxa de decaimento e à otimização da norma dos controladores chaveados, o que possibilitou encontrar melhores resultados de implementação. Por fim, foram propostos critérios menos conservadores para a análise de estabilidade e projeto de controladores chaveados, utilizando funções de Lyapunov quadráticas por partes do tipo mínimo. A vantagem desse procedimento está no aumento dos parâmetros de relaxação porém, concebido através de formulações baseadas em desigualdades matriciais bilineares (do inglês Bilinear Matrix Inequalitites - BMIs), nos quais os termos e se encontram no produto entre variáveis escalares de otimização e matrizes, que também são variáveis do procedimento de otimização. Apresentam-se, no corpo do texto, exemplos numéricos e ...
Abstract: This thesis presents results for robust stability of linear systems subject to polytopic timevarying parametric uncertainties (LPV). To start with, an improved method for the optimal gain design of robust controllers via Linear Matrix Inequalities (LMI), based on Lyapunov stability theory is presented. This new formulation was manipulated using the Finsler lemma, which enabled finding better feasibility results with the addition of extra matrices and reducing the number of LMIs. In this new equation it was included the decay rate performance index, responsible for reducing the transitional period time, as well as the controllers norm optimization, responsible for lower gains while maintaining the same project requirements efficiency. Then, due to important results in literature regarding the design of robust controllers with time-varying uncertainties, the design of switched dynamic controllers was explored by including the decay rate index and the optimization of the switched controllers norm in the equation, which allowed finding better implementation results. Finally, less conservative criteria were proposed for stability analysis and design of switched controllers using minimum-type piecewise quadratic Lyapunov functions. The advantage of this procedure lies in the increase of relaxation parameters, however, designed through formulations based on Bilinear Matrix Inequalities (BMIs), where the bilinear terms are in the product between optimization scalar variables and matrices, which are also variables on the optimization procedure. Numerical examples are presented and simulated to illustrate the efficiency of the proposed methodologies in relation to other existing throughout the text. The designed controllers were implemented using these new proposals in a Three Degrees Of Freedom (3-DOF) helicopter or in the Shake Table II (STII) + Active Mass Dumper - One Floor (AMD-1) system, in order to validate in practice the proposed theories
Doutor
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Ciuca, Frank. "Robust optimal motion-tracking control of flexible-joint robots". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq52530.pdf.
Testo completo
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Wang, Jiuguang. "Numerical Nonlinear Robust Control with Applications to Humanoid Robots". Research Showcase @ CMU, 2015. http://repository.cmu.edu/dissertations/630.
Testo completoAbstract (sommario):
Robots would be much more useful if they could be more robust. Systems that can tolerate variability and uncertainty are called robust and the design of robust feedback controllers is a difficult problem that has been extensively studied for the past several decades. In this thesis, we aim to provide a quantitative measure of performance and robustness in control design under an optimization framework, producing controllers robust against parametric system uncertainties, external disturbances, and unmodeled dynamics. Under the H1 framework, we formulate the nonlinear robust control problem as a noncooperative, two-player, zero-sum, differential game, with the Hamilton-Jacobi-Isaacs equation as a necessary and sufficient condition for optimality. Through a spectral approximation scheme, we develop approximate algorithms to solve this differential game on the foundation of three ideas: global solutions through value function approximation, local solutions with trajectory optimization, and the use of multiple models to address unstructured uncertainties. Our goal is to introduce practical algorithms that are able to address complex system dynamics with high dimensionality, and aim to make a novel contribution to robust control by solving problems on a complexity scale untenable with existing approaches in this domain. We apply this robust control framework to the control of humanoid robots and manipulation in tasks such as operational space control and full-body push recovery.
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Zhao, Shiyu. "Nonparametric robust control methods for powertrain control". Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.548802.
Testo completo
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Lin, Jong-Lick. "Control system design for robust stability and robust performance". Thesis, University of Leicester, 1992. http://hdl.handle.net/2381/34797.
Testo completoAbstract (sommario):
A central problem in control system design is how to design a controller to guarantee that the closed-loop system is robustly stable and that performance requirements are satisfied despite the presence of model uncertainties and exogenous disturbance signals. The analysis problem, that is the assessment of control systems with respect to robust stability and robust performance, can be adequately solved using the structured singular value u as introduced by Doyle. The corresponding design problem (how to choose a controller K to minimize u) is still largely unsolved, but an approximate solution can be found using Doyle's D - K iteration. In this thesis we present an alternative algorithm, called u - K iteration, which works by flattening the structured singular value u over frequency. As a prelude to this a classical loop shaping approach to robust performance is presented for SISO systems, and is also based on flattening u. In u-synthesis it is often the case that real uncertainties are modelled as complex perturbations but the conservatism so introduced can be severe. On the other hand, if real uncertainties are modelled as real perturbations then D - K iteration is not relevant. It is shown that u - K iteration still works for real perturbations. In addition, a geometric approach for computing the structured singular value for a scalar problem with respect to real and/or complex uncertainty is described. This provides insight into the relationship between real u and complex u. A robust performance problem is considered for a 2-input 2-output high purity distillation column which is an ill-conditioned plant. Analysis reveals the potentially damaging effects on robustness of ill-conditioning. A design is carried out using u - K iteration and the "optimum" u compared with that obtained by Doyle and by Freudenberg for the same problem.
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Costa, Giuseppe Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Robust Control For Gantry Cranes". Awarded by:University of New South Wales. Electrical Engineering and Telecommunications, 1999. http://handle.unsw.edu.au/1959.4/17609.
Testo completoAbstract (sommario):
In this thesis a class of robust non-linear controllers for a gantry crane system are discussed. The gantry crane has three degrees of freedom, all of which are interrelated. These are the horizontal traverse of the cart, the vertical motion of the goods (i.e. rope length) and the swing angle made by the goods during the movement of the cart. The objective is to control all three degrees of freedom. This means achieving setpoint control for the cart and the rope length and cancellation of the swing oscillations. A mathematical model of the gantry crane system is developed using Lagrangian dynamics. In this thesis it is shown that a model of the gantry crane system can be represented as two sub models which are coupled by a term which includes the rope length as a parameter. The first system will consist of the cart and swing dynamics and the other system is the hoist dynamics. The mathematical model of these two systems will be derived independent of the other system. The model that is comprised of the two sub models is verified as an accurate model of a gantry crane system and it will be used to simulate the performance of the controllers using Matlab. For completeness a fully coupled mathematical model of the gantry crane system is also developed. A detailed design of a gain scheduled sliding mode controller is presented. This will guarantee the controller's robustness in the presence of uncertainties and bounded matched disturbances. This controller is developed to achieve cart setpoint and swing control while achieving rope length setpoint control. A non gain scheduled sliding mode controller is also developed to determine if the more complex gain scheduled sliding mode controller gives any significant improvement in performance. In the implementation of both sliding mode controllers, all system states must be available. In the real-time gantry crane system used in this thesis, the cart velocity and the swing angle velocity are not directly available from the system. They will be estimated using an alpha-beta state estimator. To overcome this limitation and provide a more practical solution an optimal output feedback model following controller is designed. It is demonstrated that by expressing the system and the model for which the system is to follow in a non-minimal state space representation, LQR techniques can be used to design the controller. This produces a dynamic controller that has a proper transfer function, and negates the need for the availability of all system states. This thesis presents an alternative method of solving the LQR problem by using a generic eigenvalue solution to solve the Riccati equation and thus determine the optimal feedback gains. In this thesis it is shown that by using a combination of sliding mode and H??? control techniques, a non-linear controller is achieved which is robust in the presence of a wide variety of uncertainties and disturbances. A supervisory controller is also described in this thesis. The supervisory control is made up of a feedforward and a feedback component. It is shown that the feedforward component is the crane operator's action, and the feedback component is a sliding mode controller which compensates as the system's output deviates from the desired trajectory because of the operator's inappropriate actions or external disturbances such as wind gusts and noise. All controllers are simulated using Matlab and implemented in real-time on a scale model of the gantry crane system using the program RTShell. The real-time results are compared against simulated results to determine the controller's performance in a real-time environment.
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Kwok, Chung Tin. "Robust real-time perception for mobile robots /". Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/7017.
Testo completo
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Souza, Wallysonn Alves de [UNESP]. "Projeto de controladores robustos chaveados para sistemas não lineares descritos por modelos fuzzy Takagi-Sugeno". Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/100294.
Testo completoAbstract (sommario):
Made available in DSpace on 2014-06-11T19:30:49Z (GMT). No. of bitstreams: 0
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souza_wa_dr_ilha.pdf: 2047760 bytes, checksum: 8e0dca06c80251e6c3a1e6e46925aa1a (MD5)Esta tese propõe novos métodos de projeto de controle chaveado para algumas classes de sistemas: lineares com incertezas politópicas e não lineares incertos descritos por modelos fuzzy Takagi-Sugeno. Inicialmente são propostos métodos que utilizam uma função quadrática de Lyapunov e a estabilidade quadrática é utilizada para projetar vários ganhos do controlador, baseado em desigualdades matriciais lineares (do inglês Linear Matrix Inequalities - LMIs). Os controladores propostos são compostos por um único ganho que é escolhido por uma lei de chaveamento que retorna o menor valor da derivada temporal da função quadrática de Lyapunov. Para o caso linear, os controladores concebidos apresentam um melhor desempenho quando comparados com o controlador que emprega um único ganho de realimentação do estado normalmente implementado, e as LMIs utilizadas para encontrar os ganhos são mais relaxadas. Para o caso não linear, os controladores propostos também apresentaram um bom desempenho e eliminam a necessidade de encontrar as expressões explícitas das funções de pertinência que muitas vezes podem ter expressões longas e/ou complexas, ou serem desconhecidas devido às incertezas na planta. Em seguida foram propostos novos métodos de projeto de controle chaveado e um novo critério de estabilidade para sistemas não lineares incertos descritos por modelos fuzzy Takagi-Sugeno. O projeto do controlador chaveado é baseado na função de Lyapunov quadrática por partes do tipo mínimo e na minimização da derivada temporal desta função de Lyapunov. As condições do novo critério de estabilidade são representadas por um tipo de desigualdades matriciais bilineares (do inglês Bilinear Matrix Inequalities - BMIs) que podem ser resolvidas de forma eficiente pelo método...
This thesis proposes new switched control design methods for some classes of linear systems with polytopic uncertainties and uncertain nonlinear systems described by Takagi-Sugeno fuzzy models. Initially, are proposed methods that use a quadratic Lyapunov function and quadratic stability to design, based on Linear Matrix Inequalities (LMIs), the feedback gains. The controller gain is chosen by a switching law that returns the smallest value of the time derivative of the quadratic Lyapunov function. For the linear case, the proposed methodology presents a better performance when compared with the controller usually implemented which uses only one state feedback gain and the LMIs for finding the switched gains are more relaxed. For nonlinear plants described by Takagi-Sugeno fuzzy models, the proposed controller also presented good performance and eliminates the need to obtain the explicit expressions of the membership functions of the Takagi-Sugeno fuzzy controllers, which can often have long and/or complex expressions, or may not be known, for instance due to the plant uncertainties. The design of the switched controllers is based on a minimum-type piecewise quadratic Lyapunov function and the minimization of the time derivative of this Lyapunov function. The conditions of the new stability criterion are represented by a kind of Bilinear Matrix Inequalities (BMIs) that can be efficiently solved by the path-following method. Furthermore, the proposed switched controller can also operate even with an uncertain reference control signal. To verify the efficacy of the proposed methodology are presented numerical simulations, including robust nonlinear control designs of a ball-and-beam system and of a magnetic levitator, and finally a robust... (Complete abstract click electronic access below)
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Silva, Jefferson Leone e. "Projeto de controle robusto para acomodação de falhas no módulo do helicóptero 3-DOF /". Ilha Solteira : [s.n.], 2011. http://hdl.handle.net/11449/87099.
Testo completoAbstract (sommario):
Orientador: José Paulo Fernandes GarciaBanca: Jean Marcos de Souza Ribeiro
Banca: Cristiano Quevedo Andrea
Resumo: O principal objetivo do trabalho é explorar a técnica de controle robusto com Modos Deslizantes para a acomodação e atenuação de uma falha no sinal de controle de um helicóptero. Foram projetados dois controladores, o Controle com Estrutura Variável e Modos Deslizantes contínuo no tempo (CEV/MD), e o segundo é o Controle Discreto com Modos Deslizantes (CDMD). Foi usado um modelo matemático não linear que representa um simulador de voo (Helicóptero 3-DOF da Quanser R ), que é um equipamento útil para o ensino, aplicação e desenvolvimento de técnicas de controle robusto. Os resultados experimentais obtidos, fazem uma comparação entre o controle contínuo e o controle discreto. Para que essa comparação seja feita foi inserida uma falha no sinal de controle. Mesmo diante das diferenças na resposta do sinal de controle, entre os controladores, o sistema teve um bom desempenho quando controlado pelo CEV/MD e CDMD, mostrando assim a eficiência da técnica de controle com Modos Deslizantes
Abstract: The main objective of this work is the exploration of the robust control technique with Sliding Mode (VSC-SM) for fault accommodation and attenuation in an aircraft's propulsion system. Two controllers were designed, Variable Structure Control with Sliding Mode (VSCSM) and Discrete Control with Sliding Modes (DCSM). For that, it was used a mathematical model of a flight Simulator of a Quanser's helicopter, named as 3-DOF Helicopter, which is an excellent module for teaching, application and development of robust control techniques. The results obtained in digital simulations show great performance of the system in fault when controlled by VSC-SM and DCSM
Mestre
30
Souza, Wallysonn Alves de. "Projeto de controladores robustos chaveados para sistemas não lineares descritos por modelos fuzzy Takagi-Sugeno /". Ilha Solteira, 2013. http://hdl.handle.net/11449/100294.
Testo completoAbstract (sommario):
Orientador: Marcelo Carvalho Minhoto TeixeiraBanca: Edvaldo Assunção
Banca: Rodrigo Cardin
Banca: Ricardo Hiroshi Caldeira Takahashi
Banca: Grace Silva Deaecto
Resumo: Esta tese propõe novos métodos de projeto de controle chaveado para algumas classes de sistemas: lineares com incertezas politópicas e não lineares incertos descritos por modelos fuzzy Takagi-Sugeno. Inicialmente são propostos métodos que utilizam uma função quadrática de Lyapunov e a estabilidade quadrática é utilizada para projetar vários ganhos do controlador, baseado em desigualdades matriciais lineares (do inglês Linear Matrix Inequalities - LMIs). Os controladores propostos são compostos por um único ganho que é escolhido por uma lei de chaveamento que retorna o menor valor da derivada temporal da função quadrática de Lyapunov. Para o caso linear, os controladores concebidos apresentam um melhor desempenho quando comparados com o controlador que emprega um único ganho de realimentação do estado normalmente implementado, e as LMIs utilizadas para encontrar os ganhos são mais relaxadas. Para o caso não linear, os controladores propostos também apresentaram um bom desempenho e eliminam a necessidade de encontrar as expressões explícitas das funções de pertinência que muitas vezes podem ter expressões longas e/ou complexas, ou serem desconhecidas devido às incertezas na planta. Em seguida foram propostos novos métodos de projeto de controle chaveado e um novo critério de estabilidade para sistemas não lineares incertos descritos por modelos fuzzy Takagi-Sugeno. O projeto do controlador chaveado é baseado na função de Lyapunov quadrática por partes do tipo mínimo e na minimização da derivada temporal desta função de Lyapunov. As condições do novo critério de estabilidade são representadas por um tipo de desigualdades matriciais bilineares (do inglês Bilinear Matrix Inequalities - BMIs) que podem ser resolvidas de forma eficiente pelo método... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This thesis proposes new switched control design methods for some classes of linear systems with polytopic uncertainties and uncertain nonlinear systems described by Takagi-Sugeno fuzzy models. Initially, are proposed methods that use a quadratic Lyapunov function and quadratic stability to design, based on Linear Matrix Inequalities (LMIs), the feedback gains. The controller gain is chosen by a switching law that returns the smallest value of the time derivative of the quadratic Lyapunov function. For the linear case, the proposed methodology presents a better performance when compared with the controller usually implemented which uses only one state feedback gain and the LMIs for finding the switched gains are more relaxed. For nonlinear plants described by Takagi-Sugeno fuzzy models, the proposed controller also presented good performance and eliminates the need to obtain the explicit expressions of the membership functions of the Takagi-Sugeno fuzzy controllers, which can often have long and/or complex expressions, or may not be known, for instance due to the plant uncertainties. The design of the switched controllers is based on a minimum-type piecewise quadratic Lyapunov function and the minimization of the time derivative of this Lyapunov function. The conditions of the new stability criterion are represented by a kind of Bilinear Matrix Inequalities (BMIs) that can be efficiently solved by the path-following method. Furthermore, the proposed switched controller can also operate even with an uncertain reference control signal. To verify the efficacy of the proposed methodology are presented numerical simulations, including robust nonlinear control designs of a ball-and-beam system and of a magnetic levitator, and finally a robust... (Complete abstract click electronic access below)
Doutor
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Svendby, Eirik. "Robust control of ROV/AUVs". Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8730.
Testo completoAbstract (sommario):
In this project a robust adaptive controller has been developed for Minerva, NTNU's research ROV. The controller was tested in simulation using Matlab/Simulink with a mathematical model of the vessel. It was also tested in a practical experiment at sea, with the ROV Minerva. The simulations, the control system performs very well. The results from the practical experiment are promising, but several improvements are necessary before the system works satisfactory. The single factor which is believed to degrade the perfomance the most is an error in the mapping between thrust force and rotational speed.
32
Davis, Robert Andrew. "Model validation for robust control". Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/251990.
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Flores, Tlacuahuac Antonio. "Robust control of distillation columns". Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/8016.
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Bell, Geoffrey Laurence. "Robust model predictive control design". Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/7450.
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Bell, Margaret. "Robust optimal receding horizon control". Thesis, Imperial College London, 1997. http://hdl.handle.net/10044/1/7348.
Testo completoAbstract (sommario):
Receding horizon optimal control has a long history and provides the basis for several of the currently popular techniques for model predictive control of chemical processes. Based on a prediction of the current state of the process, derived from plant measurements, and predictions of the likely input conditions over a certain period ahead (the time horizon), optimal controls are computed to maximise a given "performance function", which can be either an economic or technical measure of performance. The state predictions are regularly updated as new measurements are made and the controls are re-computed if either the current state or the predicted input conditions change significantly. An important advantage of computing optimal controls is that this can take direct account of process operating constraints. However, general inequality constraints have always posed a difficult problem in numerical optimal control algorithms and we propose a new algorithm for dealing with this problem for systems described by DAEs of any index. Due to both the excessive time required for model development and the excessive computational time required for a full model, the on-line model is generally of a much lower complexity than the true system and although parameters in the model may be re-estimated using plant measurements, there is inevitably some uncertainty in the model predictions as well as in the input predictions. The controls must therefore be robust, giving reasonable performance in the face of variations of actual conditions from the predictions. To obtain a sufficiently simple controller, the H∞ approach has been to design a controller to perform optimally if the worst possible set of inputs and model predictions actually occur, and this can also be applied within the receding horizon optimal control framework. The result is a game, with the controls playing against the uncertain inputs and model parameters. However, this does not guarantee robustness in the presence of inequality constraints and here we propose a new simple technique for dealing with this problem, which exploits the sampling interval of the receding horizon formulation of the problem.
36
Qu, Zhihua. "Robust control of dynamic systems". Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/13452.
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黃濤 e To Wong. "Some issues on robust control". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31220113.
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Szumko, Stefan. "Robust control in state space". Thesis, University of Warwick, 1987. http://wrap.warwick.ac.uk/2886/.
Testo completoAbstract (sommario):
We consider the problem of robustness, in particular that of robust stability. Such a problem is amenable to analysis by frequency domain techniques, and also using state space methods. Using some recent state space theory yielding the exact radius of the ball around a nominally stable system within which all additive perturbations retain stability, we show how control action may be implemented to increase the radius of this ball. We present further some material on how destabilizing perturbations may be constructed from solutions of Riccati equations, and how the above mentioned radii may be found with respect to an alternative norm to the one used above. Finally we give some remarks on the use of Lyapunov functions for systems.
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Samavat, Mohmoud. "Robust control of nonlinear systems". Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327647.
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Van, Diggelen Frank Stephen Tromp. "Hadamard weighting in robust control". Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359401.
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Richards, Arthur George 1977. "Robust constrained model predictive control". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/28914.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2005.Includes bibliographical references (p. 203-209).
(cont.) multiple Uninhabited Aerial Vehicles (UAVs) demonstrate that the new DMPC algorithm offers significant computational improvement compared to its centralized counterpart. The controllers developed in this thesis are demonstrated throughout in simulated examples related to vehicle control. Also, some of the controllers have been implemented on vehicle testbeds to verify their operation. The tools developed in this thesis improve the applicability of MPC to problems involving uncertainty and high complexity, for example, the control of a team of cooperating UAVs.
This thesis extends Model Predictive Control (MPC) for constrained linear systems subject to uncertainty, including persistent disturbances, estimation error and the effects of delay. Previous work has shown that feasibility and constraint satisfaction can be guaranteed by tightening the constraints in a suitable, monotonic sequence. This thesis extends that work in several ways, including more flexible constraint tightening, applied within the prediction horizon, and more general terminal constraints, applied to ensure feasible evolution beyond the horizon. These modifications reduce the conservatism associated with the constraint tightening approach. Modifications to account for estimation error, enabling output feedback control, are presented, and we show that the effects of time delay can be handled in a similar manner. A further extension combines robust MPC with a novel uncertainty estimation algorithm, providing an adaptive MPC that adjusts the optimization constraints to suit the level of uncertainty detected. This adaptive control replaces the need for accurate a priori knowledge of uncertainty bounds. An approximate algorithm is developed for the prediction of the closed-loop performance using the new robust MPC formulation, enabling rapid trade studies on the effect of controller parameters. The constraint tightening concept is applied to develop a novel algorithm for Decentralized MPC (DMPC) for teams of cooperating subsystems with coupled constraints. The centralized MPC optimization is divided into smaller subproblems, each solving for the future actions of a single subsystem. Each subproblem is solved only once per time step, without iteration, and is guaranteed to be feasible. Simulation examples involving
by Arthur George Richards.
Ph.D.
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Çelik, Ugurcan. "Robust Booster Landing Guidance/Control". Thesis, KTH, Optimeringslära och systemteori, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279684.
Testo completoAbstract (sommario):
The space industry and the technological developments regarding space exploration hasn’t been this popular since the first moon landing. The privatization of space exploration and the vertical landing rockets made rocket science mainstream again. While being able to reuse rockets is efficient both in terms of profitability and popularity, these developments are still in their early stages. Vertical landing has challenges that, if neglected, can cause disastrous consequences. The existing studies on the matter usually don’t account for aerodynamics forces and corresponding controls, which results in higher fuel consumption thus lessening the economical benefits of vertical landing. Similar problems have been tackled in studies not regarding booster landings but regarding planetary landings. And while multiple solutions have been proposed for these problems regarding planetary landings, the fact that the reinforcement learning concepts work well and provide robustness made them a valid candidate for applying to booster landings. In this study, we focus on developing a vertical booster descent guidance and control law that’s robust by applying reinforcement learning concept. Since reinforcement learning method that is chosen requires solving Optimal Control Problems (OCP), we also designed and developed an OCP solver software. The robustness of resulting hybrid guidance and control policy will be examined against various different uncertainties including but not limited to wind, delay and aerodynamic uncertainty.Rymdindustrin och den tekniska utvecklingen av rymdutforskningen har inte varit så populär sedan den första månlandningen. Privatiseringen av utforskningen av rymden och de vertikala landningsraketerna medförde att raketvetenskapen återkom som en viktig huvudfråga igen. Även om det är effektivt att återanvända raketer i form av lönsamhet och popularitet, är denna utveckling fortfarande i sina tidiga stadier. Vertikal landning har utmaningar som, om de försummas, kan orsaka katastrofala konsekvenser. De befintliga studierna i frågan redovisar vanligtvis inte aerodynamikkrafter och motsvarande regulatorer, vilket resulterar i högre bränsleförbrukning som minskar de ekonomiska fördelarna med vertikal landning. Liknande problem har hanterats i studier som inte avsåg boosterlandningar utan om planetariska landningar. Även om flera lösningar har föreslagits för dessa problem beträffande planetariska landningar, det faktum att förstärkningsinlärningskonceptet fungerar bra och ger robusthet gjorde dem till en giltig kandidat för att ansöka om boosterlandningar. I den här studien fokuserar vi på att utveckla en lagstiftning för styrning av vertikala booster-nedstigningar som är robust genom att tillämpa koncepten inom förstärkningsinlärning. Ef- tersom förstärkt inlärningsmetod som väljs kräver lösning av optimala kontrollproblem (OCP), designade och utvecklade vi också en OCP-lösningsmjukvara. Robustheten för resulterande hybridstyrning och kontrollpolicy kommer att undersökas mot olika osäkerheter inklusive, men inte begränsat till vind, fördröjning och aerodynamisk osäkerhet.
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Braatz, Richard D. Morari Manfred Morari Manfred. "Robust loopshaping for process control /". Diss., Pasadena, Calif. : California Institute of Technology, 1993. http://resolver.caltech.edu/CaltechETD:etd-08222007-105213.
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Wong, To. "Some issues on robust control /". Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19470435.
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Fallahi, Abdolreza. "Robust control of diesel drivelines". Thesis, University of East London, 2013. http://roar.uel.ac.uk/3076/.
Testo completoAbstract (sommario):
The original contribution of this thesis is to provide insight into research of non-traditional control techniques for automotive power train applications, culminating in experimental evidence of much improved performance and reduced commissioning costs. This includes much work on the technique of Observer Based Robust Control (OBRC) which, before the research documented in this thesis commenced, was only in its infancy with some promise being shown through the simulation of electric drive applications (Dodds, 2007). The thesis, therefore, contributes to the process of bringing this new control technique nearer maturity. OBRC is based on an observer designed to provide information enabling effective control of an automotive power train application and its performance assessment. Comparison with traditional and other robust control techniques is included. The observer in OBRC is is designed to estimate the equivalent disturbance input, referred to the control input to a plant. This represents plant modelling errors as well as external disturbances. The equivalent disturbance estimate is applied to the real plant input to cancel its effect, thereby reducing the control problem to that of controlling the known real-time model of the plant employed in the observer. One of the disadvantages of conventional robust control methods, such as those based on sliding mode control, is that relatively high gain control loops are closed around the uncertain plant. This increases the risk of instability due to the dynamic elements, such as sensor lags, that are not included in the assumed plant model. The initial reason for investigating OBRC is that the high gain loops are applied to the known plant model in the observer and that the stability of these loops, taken in isolation, can therefore be guaranteed. It was found that the observer gains are limited only by the finite sampling frequency of the digital processor. In theory, infinite observer gains would yield ideal robustness. However, in practice only finite gains are possible. The aforementioned application of the equivalent disturbance estimate to the real plant input effectively transfers the high gain loops from the plant model in the observer to the real plant. This meant that closed loop stability could not be guaranteed under all circumstances. In view of this, it was decided that sliding mode control should not be excluded from the set of controllers for comparison. Since the control chatter associated with basic sliding mode control has to be eliminated for the vehicle application, polynomial control (a continuous version of the discrete RST controller) with robust pole assignment is included. This polynomial control can be regarded as equivalent to the sliding mode control with a boundary layer, but without the uncertainty associated with the choice of the boundary layer width. Two more controllers, based on the Internal Model Control (IMC) and H-infinity, are included for comparison on the basis that their design methodologies do not demand high gains. The various control techniques are demonstrated and compared via their application to Diesel Drivelines for commercial road vehicles. One of the operational problems with conventional PI engine speed controllers is the need for time consuming initial controller tuning. This requires different sets of gains for each gear selection, including idle (i.e., neutral) and later retuning to compensate for changes in the driveline characteristics with component aging. A major advantage of OBRC in this application is the elimination of the tuning procedure. Of particular interest is the fact that the order of the system is increased by two when a gear is engaged due to a vibration mode created by the finite torsional compliance of the propeller shaft and other driveline components. Since this driven mechanical load can be represented by its inverse dynamic model in a feedback path whose output acts at the same point as the control variable, the OBRC compensates for this automatically without the need for any parametric changes. The simulations and experimental work were carried out on the DAF 12 litre diesel engine. The comparative study was carried out, not only with respect to the main application of Diesel Drivelines, but also using academic examples that are even more demanding of the controllers’ capabilities. A key parameter in an engine configuration is the saturation limit on the injected fuel rate, which is highly dependent on the engine capacity from 10 litres to 16 litres. One example was introduced with a saturation block and the abilities of the various controllers under this constraint were assessed. The H-infinity controller could not handle such a saturation constraint, which is common practice in automotive applications and therefore this had to deemed unsuitable. The remaining controllers were able to operate with fuel rate saturation. The overall conclusion is that the controllers based on OBRC, polynomial control and IMC are capable of a similar performance with appropriate controller parameter settings. However all are subject to the trade-off between the conflicting requirements of short response times and robustness.
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Barbosa, Filipe Marques. "Robust recursive path-following control for autonomous heavy-duty vehicles". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18153/tde-14032019-082753/.
Testo completoAbstract (sommario):
Path following and lateral stability are crucial issues for autonomous vehicles. Moreover, these problems increase in complexity when handling heavy-duty vehicles due to their poor manoeuvrability, large sizes and mass variation. In addition, uncertainties on mass may have the potential to significantly decrease the performance of the system, even to the point of destabilising it. These parametric variations must be taken into account during the design of the controller. However, robust control techniques usually require offline adjustment of auxiliary tuning parameters, which is not practical and leads to sub-optimal operation. Hence, this work presents an approach to path-following and lateral control for autonomous heavy-duty vehicles subject to parametric uncertainties by using a robust recursive regulator. The main advantage of the proposed controller is that it does not depend on the offline adjustment of tuning parameters. Parametric uncertainties were assumed to be on the payload, and an H∞ controller was used for performance comparison in simulations. The performance of both controllers is evaluated in a double lane-change manoeuvre. Simulation results showed that the proposed method had better performance in terms of robustness, lateral stability, driving smoothness and safety, which demonstrates that it is a very promising control technique for practical applications. Ultimately, experiment tests in a rigid heavy-duty truck validate what was found in simulation results.O seguimento de caminho e a estabilidade lateral são questões cruciais para veículos autônomos. Além disso, devido à baixa capacidade de manobra, tamanho e grande variação de massa, estes problemas se tornam mais complexos quando se trata de veículos pesados. Adicionalmente, as incertezas na massa têm o potencial de diminuir significativamente o desempenho do sistema, chegando ao ponto de desestabilizá-lo, assim, essas variações paramétricas devem ser consideradas durante o projeto do controlador. No entanto, as técnicas de controle robusto geralmente exigem o ajuste off-line de parâmetros auxiliares do controlador, o que não é prático e lava a uma operação sub-ótima. Assim, este trabalho apresenta uma abordagem de controle de seguimento de caminho e controle lateral para veículos pesados autônomos sujeitos a incertezas paramétricas usando um regulador robusto recursivo. A principal vantagem deste controlador é que ele não depende do ajuste off-line de parâmetros. Assumiu-se que as incertezas paramétricas estavam na carga do veículo, e um controlador H∞ foi usado para comparar o desempenho em simulação. O desempenho de ambos os controladores é avaliado em uma manobra de mudança de faixa. Os resultados de simulação mostraram que o método proposto apresentou melhor desempenho em termos de robustez, estabilidade lateral, suavidade na condução e segurança, o que o demonstra como uma técnica de controle bastante promissora para aplicações práticas. Por fim, testes experimentais em um caminhão rígido reforçam os resultados obtidos em simulação.
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Inoue, Roberto Santos. "Controle robusto de robôs móveis com rodas". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18153/tde-26102007-184742/.
Testo completoAbstract (sommario):
Nesta dissertação é apresentado um estudo comparativo entre seis controladores H \'infinito\' não lineares aplicados em um robô móvel com rodas. Três estratégias de controle são avaliadas. Na primeira, o modelo do robô é considerado completamente conhecido. Na segunda, o modelo matemático é considerado desconhecido e é realizada uma estimativa baseada em métodos inteligentes. E finalmente, na terceira estratégia, o modelo nominal é conhecido e técnicas inteligentes são usadas para estimar somente incertezas paramétricas do robô. As técnicas inteligentes usadas são baseadas em redes neurais e em lógica fuzzy. Esses controladores são resolvidos através de desigualdades matriciais lineares (DMLs) e equações algébricas de Riccati. Todos os resultados obtidos são baseados em dados experimentais.This dissertation is present a comparative study between six nonlinear H \'infinity\' controllers applied to a wheeled mobile robot. Three control strategies are adopted. In the first, the model of the robot is considered completely known. In the second, the mathematical model is considered unknown and is accomplished an estimate based on intelligent methods. And finally, in the third strategy, the nominal model is known and intelligent techniques are used only to estimate parametric uncertainties of the robot. The intelligent techniques used are based in neural networks and in fuzzy logic. These controllers are solved via linear matrix inequalities (LMIs) and algebraic Riccati equations. All results obtained are based in experimental data.
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Imura, Jun-ichi. "STUDIES ON ROBUST CONTROL OF NONLINEAR SYSTEMS INCLUDING ROBOT MANIPULATORS". Kyoto University, 1994. http://hdl.handle.net/2433/74662.
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McCaskey, Suzanne D. "Robust design of dynamic systems". Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/24223.
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Sorour, Mohamed. "Motion discontinuity-robust controller for steerable wheeled mobile robots". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS090/document.
Testo completoAbstract (sommario):
Les robots mobiles à roues orientables gagnent de la mobilité en employant des roues conventionnelles entièrement orientables, comportant deux joints actifs, un pour la direction et un autre pour la conduite. En dépit d'avoir seulement un degré de mobilité (DOM) (défini ici comme degrés de liberté instantanément autorisés DOF), correspondant à la rotation autour du centre de rotation instantané (ICR), ces robots peuvent effectuer des trajectoires planaires complexes de $ 2D $. Ils sont moins chers et ont une capacité de charge plus élevée que les roues non conventionnelles (par exemple, Sweedish ou Omni-directional) et, en tant que telles, préférées aux applications industrielles. Cependant, ce type de structure de robot mobile présente des problèmes de contrôle textit {basic} difficiles de la coordination de la direction pour éviter les combats d'actionneur, en évitant les singularités cinématiques (ICR à l'axe de la direction) et les singularités de représentation (du modèle mathématique). En plus de résoudre les problèmes de contrôle textit {basic}, cette thèse attire également l'attention et présente des solutions aux problèmes de textit {niveau d'application}. Plus précisément, nous traitons deux problèmes: la première est la nécessité de reconfigurer "de manière discontinue" les articulations de direction, une fois que la discontinuité dans la trajectoire du robot se produit. Une telle situation - la discontinuité dans le mouvement du robot - est plus susceptible de se produire de nos jours, dans le domaine émergent de la collaboration homme-robot. Les robots mobiles qui fonctionnent à proximité des travailleurs humains en mouvement rapide rencontrent généralement une discontinuité dans la trajectoire calculée en ligne. Le second apparaît dans les applications nécessitant que l'angle de l'angle soit maintenu, certains objets ou fonctionnalités restent dans le champ de vision (p. Ex., Pour les tâches basées sur la vision) ou les changements de traduction. Ensuite, le point ICR est nécessaire pour déplacer de longues distances d'un extrême de l'espace de travail à l'autre, généralement en passant par le centre géométrique du robot, où la vitesse du robot est limitée. Dans ces scénarios d'application, les contrôleurs basés sur l'ICR à l'état de l'art conduiront à des comportements / résultats insatisfaisants. Dans cette thèse, nous résolvons les problèmes de niveau d'application susmentionnés; à savoir la discontinuité dans les commandes de vitesse du robot et une planification meilleure / efficace pour le contrôle du mouvement du point ICR tout en respectant les limites maximales de performance des articulations de direction et en évitant les singularités cinématiques et représentatives. Nos résultats ont été validés expérimentalement sur une base mobile industrielleSteerable wheeled mobile robots gain mobility by employing fully steerable conventional wheels, having two active joints, one for steering, and another for driving. Despite having only one degree of mobility (DOM) (defined here as the instantaneously accessible degrees of freedom DOF), corresponding to the rotation about the instantaneous center of rotation (ICR), such robots can perform complex $2D$ planar trajectories. They are cheaper and have higher load carrying capacity than non-conventional wheels (e.g., Sweedish or Omni-directional), and as such preferred for industrial applications. However, this type of mobile robot structure presents challenging textit{basic} control issues of steering coordination to avoid actuator fighting, avoiding kinematic (ICR at the steering joint axis) and representation (from the mathematical model) singularities. In addition to solving the textit{basic} control problems, this thesis also focuses attention and presents solutions to textit{application level} problems. Specifically we deal with two problems: the first is the necessity to "discontinuously" reconfigure the steer joints, once discontinuity in the robot trajectory occurs. Such situation - discontinuity in robot motion - is more likely to happen nowadays, in the emerging field of human-robot collaboration. Mobile robots working in the vicinity of fast moving human workers, will usually encounter discontinuity in the online computed trajectory. The second appears in applications requiring that some heading angle is to be maintained, some object or feature stays in the field of view (e.g., for vision-based tasks), or the translation verse changes. Then, the ICR point is required to move long distances from one extreme of the workspace to the other, usually passing by the robot geometric center, where the feasible robot velocity is limited. In these application scenarios, the state-of-art ICR based controllers will lead to unsatisfactory behavior/results. In this thesis, we solve the aforementioned application level problems; namely discontinuity in robot velocity commands, and better/efficient planning for ICR point motion control while respecting the maximum steer joint performance limits, and avoiding kinematic and representational singularities. Our findings has been validated experimentally on an industrial mobile base