Top PDF Stochastic System Design and Applications to Stochastically Robust Structural Control

Stochastic System Design and Applications to Stochastically Robust Structural Control

Stochastic System Design and Applications to Stochastically Robust Structural Control

This system can be easily represented in the augmented form of Figure 2.1. Thus the general stochastic system design formulation discussed earlier can be naturally extended to control applications to develop a robust-to-uncertainties nonlinear controller design methodology. The simulation-based methodology discussed earlier will contribute to explicit consideration of all important, linear or nonlinear, characteristics of the system model at the design stage, but will lead to a challenging controller optimization problem, especially for systems that include higher-order controllers with large dimensional parameter vectors. For controlled systems it is interesting to compare how the stochastic design approach compares to classical methodologies that have become the standard tools for controller synthesis. Some insight to this question will be given in Chapter 3. Because of their greater familiarity in the control literature, Chapter 3 will address the design of control laws for linear structural systems with probabilistic model uncertainty, under stationary stochastic excitation. An analytical approach, motivated by the simplicity of the models, will be discussed for this design problem that gives useful insight in the characteristics of the controller synthesis and allows for direct comparison to other controller design methods that have been proposed for such applications.
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Robust space trajectory design using belief stochastic optimal control

Robust space trajectory design using belief stochastic optimal control

The final goal is the generation of optimal nominal trajectories which are most robust and reliable to the possible uncertainty realisations, that is optimally minimising a statistical objective index while respecting stochastic constraints. Moreover, this method improves the overall trajectory design process by helping reducing the number of design iterations. More in detail, first a formulation based on the Belief Markov Decision Process (BMDP) [14] is introduced to directly model the problem in terms of uncertainty distributions. This is particularly suited to model the inference step necessary for the state knowledge update when an orbit determination campaign is carried out. While BMDP is typically used to find optimal closed-loop controls in problems with a discrete state space, the formulation presented here is general enough to address both optimal open- and closed-loop control laws in continuous state space applications with sparse observation feedback. The optimised solution resulting from this approach is highly informative as it determines both the nominal control profile and a general control policy for possible deviations due to uncertainty, hence directly providing empirical margins for correction manoeuvres. Furthermore, BMDP is defined for precise probability distributions only, whereas the formulation employed here can accommodate epistemic and imprecise uncertainties as well. In addition, such formulation is generalised to encompass the class of problems involving sensor control, i.e.
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SMC design for robust H∞ control of uncertain stochastic delay systems

SMC design for robust H∞ control of uncertain stochastic delay systems

+ ( C d + ∆ C d ( t )) x ( t − τ( t )) ] d w( t ), (1) where it is assumed that there is matrix G ∈ R m × n such that det ( GB ) 6= 0 and GD = 0 (2) with det ( · ) denoting the determinant of a matrix. However, these existing results employ assumptions such as (2) on the structure of the control system such that their controller design do not need to deal with stochastic perturbation and hence they can use the SMC design method for deterministic systems (see Remark 1 and 4 in Huang and Deng (2008a)). These existing results may be considered as studies of SMC with stochastic perturbation in sliding mode. But such an assumption may be too restrictive for stochastic systems in many practical situations.
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DESIGN AND VERIFICATION OF ROBUST ROUTER FOR SYSTEM ON CHIP APPLICATIONS

DESIGN AND VERIFICATION OF ROBUST ROUTER FOR SYSTEM ON CHIP APPLICATIONS

1 Associate Professor, 2 PG Scholar, M.Tech(DSCE), ECE Department, PBR VITS, KAVALI, (India) ABSTRACT Through this paper the attempt is to give a onetime networking solution by the means of merging the VLSI field with the networking field. As now a days the router is the key player in networking domain. So the focus remains on that itself to get a good control over the network, Networking router today are with minimum pins and to enhance the network. By going for the bridging loops which effect the latency and security concerns. The other is of multiple protocols being used in the industry today. Through this paper the attempt is to overcome the security and latency issues with protocol switching technique embedded in the router engine itself. This paper is based on the hardware coding which will give a great impact on the latency issue as the hardware itself will be designed according to the need. In this paper the attempt is to provide a multipurpose networking router by means of Verilog code, by this one can maintain the same switching speed with more secured way of approach have even the packet storage buffer on chip being generated by code in our design in the so we this can also be as the self-independent router called as the VLSI Based router. This paper has the main focus on the implementation of hardware IP router. The approach here is that router will process multiple incoming IP packets with different versions of protocols simultaneously and even it is going to hold true for the IPv4 as well as for IPv6. With the approach of increasing switching speed of a routing per packet for both the current trend protocols. This paper thus is going to be a revolutionary enhancement in the domain of networking.
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Automated robust control system design for variable speed drives

Automated robust control system design for variable speed drives

representation. The most commonly used operator, illustrated in figure 2.2 is subtree crossover, in which an entire subtree is swapped between two parents [14], [23]. Bacterial Foraging: Bacterial Foraging is a new evolutionary computational method proposed by Kevin Passino[29] in 2002. In this scheme, the foraging (methods for locating, handling and ingesting food) behaviour of E. coli bacteria present in our intestines is mimicked. The approach incorporates concepts of evolution and natural selection and as such it is suitably regarded as an evolutionary algorithm. Although it also incorporates concepts of Swarm Intelligence, the fundamental idea behind the algorithms development is based upon the natural selection of bacteria with good foraging habits and the evolution of better strategies using the good foragers as the parents. They undergo different stages such as chemotaxis, swarming, reproduction and elimination and dispersal. This evolutionary approach has also been adopted in achieving the aims of the research project and more detail is provided in section 3.3. In the last decade, within the field of control and instrumentation engineering, evolu- tionary algorithms have been receiving increasing attention because of their potential to deal with problems not amenable to existing design techniques. Through the adoption of EA, there are more novel techniques being developed that are aimed at designing more efficient controllers for variable speed drives and a number of such EA design techniques have also been successfully implemented for such applications. In [12] and [16], automated design of controllers for variable speed drives have been investigated.
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Optimal design of a novel tuned mass-damper-inerter (TMDI) passive vibration control configuration for stochastically support-excited structural systems

Optimal design of a novel tuned mass-damper-inerter (TMDI) passive vibration control configuration for stochastically support-excited structural systems

of the inerter accommodates viscous dampers with much higher damping coefficients compared to an optimally tuned classical TMD. Overall, the herein reported analytical and numerical data provide evidence that the proposed TMDI configuration offers a promising solution for passive vibration control of stochastically support-excited systems. This is due to the mass amplification effect stemming from the unique mechanical properties of the inerter device which improves the effectiveness of the classical TMD for vibration suppression in all cases considered. Further on-going research efforts by the authors are directed towards establishing alternative configurations/topologies to combine TMDs with inerter devices to control the dynamic response of various mechanical and civil engineering structures and structural systems for stochastic and deterministic excitations and for various response minimization criteria.
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Design of DC-DC Converter System for Structural Vibration Control

Design of DC-DC Converter System for Structural Vibration Control

BMS College of Engineering, Bengaluru, Karnataka, India 1 CSIR-National Aerospace Laboratories, Bengaluru, Karnataka, India 2 ABSTRACT: This paper presents the design of DC-DC Converter system for structural vibration control. The structural vibration control is carried out using the phenomenon called as the Active Vibration Control. The biasing input voltage range for the DC-DC converter is from 28 V to 32 V, and the output voltage range is from -40V to +150V. This is achieved by using a modified Buck-Boost DC-DC converter. Reason for selecting the buck-boost converter is that it converts DC voltage efficiently to either a lower or higher voltage. So it is best suitable for AVC applications which require both positive and negative voltage. The commonly used buck-boost converter requires a single controllable switch like MOSFET. The switching frequency range for the converter is of 1 kHz. The output voltage is observed for different PWM signal variation. The DC-DC buck-boost converter is designed in MATLAB/Simulink platform.
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Remotus. Robust radio remote control for safety critical industrial applications ROBUST SWEDISH DESIGN SINCE 1918

Remotus. Robust radio remote control for safety critical industrial applications ROBUST SWEDISH DESIGN SINCE 1918

REMOTUS Mercury DP-Link REMOTUS Mercury RX-Link The Remotus Mercury DP-Link is a system for wireless data transmission between two Profibus DP busses. The system enables data communication between two busses within a large area or when direct bus connections are not possible. The units are connected as DP slaves to the Profibus DP field bus. Transmission time for 16 bytes-in and 16 bytes-out in both directions over the radio link is less than 100 ms. The units must be connected to both nodes in a Profibus DP master to enable data communication. There is a serial asynchronous communication channel for communication, for example, with scales and position sensors. The Remotus Mercury DP-Link has a powerful, built-in programmable logic controller (PLC) system that handles sophisticated data processing. The system has a 14-bit address that allows for 16,384 different addresses, a serial, asynchronous communication channel for communicating with scales, position sensors, and the like, and a built-in monitor for test and parameter settings. There are also indicators for different system functions (status, outputs).
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Robust Control System Design for Multivariable Plants with Lightly Damped Modes

Robust Control System Design for Multivariable Plants with Lightly Damped Modes

Reinelt Wolfgang, «Robust control of a Two-Mass-Spring System subject to its Input Constraints», American Control Conference, Chicago, USA 28-30 June 2000 Spencer Jr B.F., S.J. Dyke and H.S. Deoskar, «Benchmark Problems in structural control Part I: Active Mass Driver System», Proceedings of the 1997 ASCE Structures Congress, Portland, Oregon, April 13-16,1997.

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Stability analysis and robust control of power networks in stochastic environment

Stability analysis and robust control of power networks in stochastic environment

We further study the vulnerability of the power network to uncertainties in sensors and actu- ators such as PMUs and FACTS devices. The Gaussian uncertainty appears multiplicative in the power system dynamics which makes the analysis and control design challenging. In this scenario, the problem of designing a robust wide area control for damping the inter-area oscillations in a power network (with stochastic uncertainty) is studied. The power network with various sources of uncertainty is modeled as an NCS with stochastic uncertainty. The developed system theoretic framework is applied to analyze resiliency and design of robust mitigation strategies against vul- nerabilities that arise from the cyber component of the power system. The framework allows us to characterize this loss of performance precisely and identify the critical value of stochastic uncer- tainty beyond which system losses stability. One of the unique features of our proposed modeling framework is that the stochastic uncertainties enter both additive and multiplicative in the system dynamics. The multiplicative nature of stochastic uncertainty allows us to use this framework to analyze vulnerabilities that appear parametric in the system dynamics such as a change in network topology or stochasticity in system parameters. Analytical bounds for the maximum tolerable variance for the noise in the communication channel without losing the stochastic stability of the network are computed. Our theoretical framework is also used to determine the most critical mea- surement/control input that can tolerate the least amount of noise variance. We further provide LMI-based optimization formulation to design a controller robust to communication channel noise.
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Robust Control of Delayed Fin Stabilizer Stochastic Systems of a Ship

Robust Control of Delayed Fin Stabilizer Stochastic Systems of a Ship

In this paper, the robust control problem of delayed fin stabilizer stochastic system of a ship with uncertainty is discussed and investigated. To describe the system, Linear Parameter Varying (LPV) modelling approach and multiplicative noise term are used to establish the corresponding polynomial model. For simulating the general operating environment, the delay effect is considered as time-varying case. Moreover, the gain-scheduled control scheme is employed to discuss the delay-dependent stabilization problem and to design the corresponding controller. Moreover, a novel Lyapunov-Kravoskii function is proposed by using parameter-dependent matrix and integral Lyapunov function to reduce the conservatism of the derived stability conditions. In order to apply the convex optimization algorithm, the derived conditions are converted into Linear Matrix Inequality (LMI) form. By solving the conditions, some feasible solutions can be obtained to establish the controller to guarantee robust stability of the delayed fin stabilizer stochastic system of a ship in the mean square.
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Robust Path Planning and Feedback Design under Stochastic Uncertainty

Robust Path Planning and Feedback Design under Stochastic Uncertainty

I. Introduction Autonomous vehicles such as Unmanned Air Vehicles (UAVs) need to be able to plan trajectories to a specified goal that avoid obstacles, and are robust to the uncertainty that arises in the real world. Sources of uncertainty include uncertain state estimation, disturbances and modeling errors. While much prior research has focused on robustness to set-bounded uncertainty, 1–4 many sources of uncertainty, such as wind disturbances, are most naturally characterized using stochastic models. 5 With stochastic uncertainty, it is typically not possible to guarantee mission success, defined as reaching the goal region and avoiding all obstacles, since there is always a small probability that a very large disturbance will occur. We can, however, define robustness in terms of chance constraints. These require that mission failure occurs with at most a user-specified probability. Such constraints enable the operator to trade conservatism against performance; a plan with a very low probability of failure will typically require more fuel, or time, to complete. In this paper we are concerned with the problem of optimal chance constrained path planning with feedback design. That is, we would like to design a sequence of feedforward control inputs and a feedback controller that minimizes cost, such as fuel use, while ensuring that the probability of failure is below the required threshold. We are concerned with discrete-time linear systems; prior work showed that a UAV operating at a constant altitude as well as other autonomous vehicles can be approximated as such a system, subject to velocity and turn rate constraints. 6, 7 A number of recent articles have addressed parts of this problem, which we summarize here.
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Bayesian Updating, Model Class Selection and Robust Stochastic Predictions of Structural Response

Bayesian Updating, Model Class Selection and Robust Stochastic Predictions of Structural Response

1 Departments of Mechanical and Civil Engineering, and Computing and Mathematical Sciences, California Institute of Technology, Pasadena, CA, USA email: jimbeck@caltech.edu modeling and excitation uncertainty. A general framework for this is presented which uses probability as a multi-valued conditional logic for quantitative plausible reasoning in the presence of uncertainty due to incomplete information. The fundamental probability models that represent the structure’s uncertain behavior are specified by the choice of a stochastic system model class: a set of input-output probability models for the structure and a prior probability distribution over this set that quantifies the relative plausibility of each model. A model class can be constructed from a parameterized deterministic structural model by stochastic embedding utilizing Jaynes’ Principle of Maximum Information Entropy. Robust predictive analyses use the entire model class with the probabilistic predictions of each model being weighted by its prior probability, or if structural response data is available, by its posterior probability from Bayes’ Theorem for the model class. Additional robustness to modeling uncertainty comes from combining the robust predictions of each model class in a set of competing candidates weighted by the prior or posterior probability of the model class, the latter being computed from Bayes’ Theorem. This higher- level application of Bayes’ Theorem automatically applies a quantitative Ockham razor that penalizes the data-fit of more complex model classes that extract more information from the data. Robust predictive analyses involve integrals over high- dimensional spaces that usually must be evaluated numerically. Published applications have used Laplace's method of asymptotic approximation or Markov Chain Monte Carlo algorithms.
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Virtual sensors for active noise control in acoustic–structural coupled enclosures using structural sensing: robust virtual sensor design

Virtual sensors for active noise control in acoustic–structural coupled enclosures using structural sensing: robust virtual sensor design

P _ j ¼ A j P j þ P j A T j þ B dj Q d B T dj P j C T pj Q 1 n C pj P j ¼ 0: (9) The Kalman gain can then be obtained as K pj ¼ P j C T pj Q 1 n : (10) Although such a Kalman-based virtual sensor can perform well under a nominal system, there is no guarantee that it would perform reasonably well when the system dynamic is no longer at the nominal case. The Kalman filter can be designed for a better sensing performance, though it is still limited for the nominal system. It should be noted that obtaining a virtual sensor filter based on the direct inversion of transfer function associated with structural sensor output, G pd , is generally not a practical solution because of potential problems with the stability, causality, and noise sensitivity of such a filter. Transfer function G pd is generally not a col- located system with respect to the disturbance input, i.e., it is a non-minimum phase system which has an unstable inver- sion. Further, since a vibro-acoustic dynamic model always contains inaccuracies particularly at anti-resonance regions where the signal-to-noise is low, a direct inversion of the model may lead to a virtual sensor filter with high noise sen- sitivity due to its excessive sensor gain. In this case, the Kal- man filter can provide a practical alternative to designing a virtual sensor, although a consideration of robustness in the design is necessary.
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Design Of Control System Instrumentation Based On Structural Modeling With Criteria Of Quality Of Control (Qoc) And Cost

Design Of Control System Instrumentation Based On Structural Modeling With Criteria Of Quality Of Control (Qoc) And Cost

[15] C. Roucairol. Solving hard combinatorial optimization problems, in Proceeding of CESA, pp. 66-72, 1998. Zine-eddine MEGUETTA was born in DREAN El-Tarf, Algeria, in 11 January 1988. He received the master 2 research on automatic control in 2011 from the University Badji Mokhtar Annaba, Algeria. He is currently pursuing his PhD degree with the laboratory LAGIS of university Lille-1, France. His research interests include the design of control system instrumentation, dependability and diagnostic, fault tolerant systems, quality of performance, reliability and their applications in embedded systems, industrial process.
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Robust variance-constrained H∞ control for stochastic systems with multiplicative noises

Robust variance-constrained H∞ control for stochastic systems with multiplicative noises

Submitted by J.A. Filar Abstract In this paper, the robust variance-constrained H ∞ control problem is considered for uncertain stochastic systems with multiplicative noises. The norm-bounded parametric uncertainties enter into both the system and output matrices. The purpose of the problem is to design a state feedback controller such that, for all admissible parameter uncertainties, (1) the closed-loop system is exponentially mean-square quadratically stable; (2) the individual steady-state variance satisfies given upper bound constraints; and (3) the pre- scribed noise attenuation level is guaranteed in an H ∞ sense with respect to the additive noise disturbances. A general framework is established to solve the addressed multiobjective problem by using a linear matrix inequality (LMI) approach, where the required stability, the H ∞ characterization and variance constraints are all easily enforced. Within such a framework, two additional optimization problems are formulated: one is to optimize the H ∞ performance, and the other is to minimize the weighted sum of the system state variances. A numerical example is provided to illustrate the effectiveness of the proposed design algorithm.
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Robust stochastic analysis with applications

Robust stochastic analysis with applications

In other words, our second approach covers all previously known techniques of inte- gration in model free financial mathematics, while the first approach is much more general but at the price of leaving the Banach space world. There is only one pitfall: the rough path integral is usually defined as a limit of compensated Riemann sums which have no obvious financial interpretation. This sabotages our entire philosophy of only using financial arguments. That is why we show that under some weak condition every rough path integral R F dS is given as limit of non-anticipating Riemann sums that do not need to be compensated – the first time that such a statement is shown for general rough path integrals. Of course, this will not change anything in concrete applications, but it is of utmost importance from a philosophical point of view. Indeed, the justification for using the Itˆ o integral in classical financial mathematics is crucially based on the fact that it is the limit of non-anticipating Riemann sums, even if in “every day applications” one never makes reference to that; see for example the discussion in [Lyo95b].
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Passification-based robust flight control system design

Passification-based robust flight control system design

Keywords: flight control, uncertain dynamic systems, shunt compensation, robustness 1. INTRODUCTION Modern high-maneuverable aircrafts, such as fighters, op- erate over a wide range of flight conditions, which vary with altitude, Mach number, angle-of-attack, and engine thrust. The mechanical characteristics of the airframe, such as the center of gravity, change as well. The aircraft autopilot has to be able to produce a response that is accurate and fast despite severe variations in speed and altitude of the airframe or, in the other words, in the face of large parametric uncertainty (Tsourdos and White, 2001; Singh et al., 2003; Belkharraz and Sobel, 2007). The promising way to fulfill these requirements is application of the adaptive control technique. The adaptation method has to meet the conflicting requirements on the tuning rate and performance quality under the conditions of lack of the aircraft state measurements (Andrievsky et al., 1996b;
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Robust stochastic control and equivalent martingale measures

Robust stochastic control and equivalent martingale measures

Abstract: We study a class of robust, or worst case scenario, optimal control problems for jump diffusions. The scenario is represented by a probability measure equivalent to the initial probability law. We show that if there exists a control that annihilates the noise coefficients in the state equation and a scenario which is an equivalent martingale measure for a specific process which is related to the control-derivative of the state process, then this control and this probability measure are optimal. We apply the result to the problem of consumption and portfolio optimization under model uncertainty in a financial market, where the price process S(t) of the risky asset is modeled as a geometric Itô-Lévy process. In this case the optimal scenario is an equivalent local martingale measure of S(t). We solve this problem explicitly in the case of logarithmic utility functions.
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Robust Portfolio Control with Stochastic Factor Dynamics

Robust Portfolio Control with Stochastic Factor Dynamics

Their model uses linear dynamics and a quadratic objec- tive to achieve tractability with considerable flexibility and generality that lends itself to further study. Their analy- sis, motivated by realistic trading strategies, focuses on the impact of the speed of mean reversion in factor dynamics and how this affects portfolio control and, ultimately, equi- librium asset prices. By building on their framework, we retain a high degree of tractability, and we can study the effect of robustness in a current and independent model, rather than in a model introduced specifically for the com- parison. As a by-product, we can also see the effect of model uncertainty on factor dynamics and the factor model of returns: the adversary in the robust formulation can per- turb both, and the adversary’s optimal choice points to the ways in which the investor is most vulnerable to model error. We test our portfolio rules on the same commodity futures as Gârleanu and Pedersen (2013). Briefly, we find that robustness leads to better performance in out-of-sample tests in which the model is reestimated on a rolling win- dow; robust rules guard against model and estimation error by trading less aggressively on signals from the factors.
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