Showing papers on "Observer (quantum physics) published in 2012"
TL;DR: This technical note considers the cooperative output regulation of linear multi-agent systems and devising a distributed observer can solve the problem by a dynamic full information distributed control scheme.
Abstract: In this technical note, we consider the cooperative output regulation of linear multi-agent systems. The overall system consists of two groups of subsystems. While the first group of subsystems can access the exogenous signal, the second cannot. As a result, the problem cannot be solved by the decentralized approach. By devising a distributed observer, we can solve the problem by a dynamic full information distributed control scheme. The problem can also be viewed as a generalization of some results of the leader-following consensus problem of multi-agent systems.
588 citations
TL;DR: The goal of this technical note is to design interval observers for a class of nonlinear continuous-time systems and shows that it is usually possible to design an interval observer for linear systems by means of linear time-invariant changes of coordinates even if the system is not cooperative.
Abstract: The goal of this technical note is to design interval observers for a class of nonlinear continuous-time systems. The first part of this work shows that it is usually possible to design an interval observer for linear systems by means of linear time-invariant changes of coordinates even if the system is not cooperative. This result is extended to a class of nonlinear systems using partial exact linearisations. The proposed observers guarantee to enclose the set of system states that is consistent with the model, the disturbances and the measurement noise. Moreover, it is only assumed that the measurement noise and the disturbances are bounded without any additional information such as stationarity, uncorrelation or type of distribution. The proposed observer is illustrated through numerical simulations.
434 citations
01 Jun 2012
TL;DR: This paper considers the cooperative output regulation of linear multi-agent systems under switching network and develops a distributed observer network that can solve the problem by both dynamic state feedback control and dynamic measurement output feedback control.
Abstract: In this paper, we consider the cooperative output regulation of linear multi-agent systems under switching network. The problem can be viewed as a generalization of the leader-following consensus problem of multi-agent systems. Due to the limited information exchanges of different subsystems, the problem cannot be solved by the decentralized approach and is not allowed to be solved by the centralized control. By devising a distributed observer network, we can solve the problem by both dynamic state feedback control and dynamic measurement output feedback control. As an application of our main result, we show that a special case of our results leads to the solution of the leader-following consensus problem of linear multi-agent systems.
389 citations
TL;DR: It is shown that the proposed control law can guarantee that all the signals of the resulting closed-loop system are semiglobally uniformly ultimately bounded and that the observer and tracking errors converge to a small neighborhood of the origin.
Abstract: This paper is concerned with the problem of adaptive fuzzy tracking control for a class of uncertain multiple-input-multiple-output (MIMO) pure-feedback nonlinear systems with immeasurable states. The dynamic output feedback strategy begins with a state observer. Fuzzy logic systems are utilized to approximate the unknown nonlinear functions. The filtered signals are introduced to circumvent algebraic loop problem encountered in the implementation of the controller, and an adaptive fuzzy output feedback is obtained via a backstepping recursive design technique. It is shown that the proposed control law can guarantee that all the signals of the resulting closed-loop system are semiglobally uniformly ultimately bounded and that the observer and tracking errors converge to a small neighborhood of the origin. Simulation studies are included to illustrate the effectiveness and potentials of the proposed techniques.
330 citations
TL;DR: A direct Lyapunov method for the stability analysis of the resulting closed-loop system is developed, which is based on the application of Wirtinger's and Halanay's inequalities.
281 citations
Journal Article•
TL;DR: A new unified formula is developed that incorporates the effects of luminance, size of the adapting field, age of the observer, and whether one or both eyes are adapted.
Abstract: The size of the pupil has a large effect on visual function, and pupil size depends mainly on the adapting luminance, modulated by other factors. Over the last century, a number of formulas have been proposed to describe this dependence. Here we review seven published formulas and develop a new unified formula that incorporates the effects of luminance, size of the adapting field, age of the observer, and whether one or both eyes are adapted. We provide interactive demonstrations and software implementations of the unified formula.
279 citations
TL;DR: This paper is concerned with the problem of robust H∞ output feedback control for a class of continuous-time Takagi-Sugeno (T-S) fuzzy affine dynamic systems using quantized measurements and the solutions are formulated in the form of linear matrix inequalities (LMIs).
Abstract: This paper is concerned with the problem of robust H∞ output feedback control for a class of continuous-time Takagi-Sugeno (T-S) fuzzy affine dynamic systems using quantized measurements. The objective is to design a suitable observer-based dynamic output feedback controller that guarantees the global stability of the resulting closed-loop fuzzy system with a prescribed H∞ disturbance attenuation level. Based on common/piecewise quadratic Lyapunov functions combined with S-procedure and some matrix inequality convexification techniques, some new results are developed to the controller synthesis for the underlying continuous-time T-S fuzzy affine systems with unmeasurable premise variables. All the solutions to the problem are formulated in the form of linear matrix inequalities (LMIs). Finally, two simulation examples are provided to illustrate the advantages of the proposed approaches.
243 citations
TL;DR: This paper addresses the problem of fault-tolerant control for Takagi-Sugeno (T-S) fuzzy systems with actuator faults with a general actuator fault model, and sliding-mode observers (SMOs) are designed to provide a bank of residuals for fault detection and isolation.
Abstract: This paper addresses the problem of fault-tolerant control for Takagi-Sugeno (T-S) fuzzy systems with actuator faults First, a general actuator fault model is proposed, which integrates time-varying bias faults and time-varying gain faults Then, sliding-mode observers (SMOs) are designed to provide a bank of residuals for fault detection and isolation Based on Lyapunov stability theory, a novel fault-diagnostic algorithm is proposed to estimate the actuator fault, which removes the classical assumption that the time derivative of the output errors should be known as in some existing work Further, a novel fault-estimation observer is designed Utilizing the estimated actuator fault, an accommodation scheme is proposed to compensate for the effect of the fault In addition, a sufficient condition for the existence of SMOs is derived according to Lyapunov stability theory Finally, simulation results of a near-space hypersonic vehicle are presented to demonstrate the efficiency of the proposed approach
239 citations
TL;DR: An algorithm for estimation of bias in the body-fixed vector measurements, which is analyzed in combination with the attitude and gyro bias observer, and proves semiglobal stability without either of these assumptions when a parameter projection is added.
Abstract: We present two results on attitude estimation using vector and rate gyro measurements. The first result concerns an observer previously presented by Hamel, Mahony, and Pflimlin, with proven stability results when i) the reference vectors are stationary; or ii) the gyro measurements are unbiased. We prove semiglobal stability without either of these assumptions when a parameter projection is added, and convergence from all initial attitudes when using a resetting strategy. The second result is an algorithm for estimation of bias in the body-fixed vector measurements, which is analyzed in combination with the attitude and gyro bias observer.
200 citations
TL;DR: This paper studies the finite-time H∞ control problem for time-delay nonlinear jump systems via dynamic observer-based state feedback by the fuzzy Lyapunov-Krasovskii functional approach and demonstrates the effectiveness of the proposed design approach.
Abstract: This paper studies the finite-time H∞ control problem for time-delay nonlinear jump systems via dynamic observer-based state feedback by the fuzzy Lyapunov-Krasovskii functional approach The Takagi-Sugeno (T-S) fuzzy model is first employed to represent the presented nonlinear Markov jump systems (MJSs) with time delays Based on the selected Lyapunov-Krasovskii functional, the observer-based state feedback controller is constructed to derive a sufficient condition such that the closed-loop fuzzy MJSs is finite-time bounded and satisfies a prescribed level of H∞ disturbance attenuation in a finite time interval Then, in terms of linear matrix inequality (LMIs) techniques, the sufficient condition on the existence of the finite-time H∞ fuzzy observer-based controller is presented and proved The controller and observer can be obtained directly by using the existing LMIs optimization techniques Finally, a numerical example is given to illustrate the effectiveness of the proposed design approach
196 citations
TL;DR: This technical note shows that the same continuous-time system under the same assumption can be globally stabilized by a sampled-data output feedback controller whose observer and control law are discrete-time and linear, and hence can be easily implemented by computers.
Abstract: In the literature, it has been proved that under a lower-triangular linear growth condition, a class of uncertain nonlinear systems can be globally stabilized by a linear state feedback controller (Tsinias) and later by a linear output feedback controller (Qian and Lin), both in the continuous-time form. This technical note shows that the same continuous-time system under the same assumption can be globally stabilized by a sampled-data output feedback controller whose observer and control law are discrete-time and linear, and hence can be easily implemented by computers.
TL;DR: This paper studies the problem of robust fault estimation (FE) observer design for discrete-time Takagi-Sugeno (T-S) fuzzy systems via piecewise Lyapunov functions through a novel framework of the FE observer with less conservatism.
Abstract: This paper studies the problem of robust fault estimation (FE) observer design for discrete-time Takagi-Sugeno (T-S) fuzzy systems via piecewise Lyapunov functions. Both the full-order FE observer (FFEO) and the reduced-order FE observer (RFEO) are presented. The objective of this paper is to establish a novel framework of the FE observer with less conservatism. First, under the multiconstrained design, an FFEO is proposed to achieve FE for discrete-time T-S fuzzy models. Then, using a specific coordinate transformation, an RFEO is constructed, which results in a new fault estimator to realize FE using current output information. Furthermore, by the piecewise Lyapunov function approach, less conservative results on both FFEO and RFEO are derived by introducing slack variables. Simulation results are presented to illustrate the advantages of the theoretic results that are obtained in this paper.
TL;DR: Two kinds of observer-based sensorless predictive torque control methods are proposed, based on examining feasible voltage vectors in a prescribed cost function and a novel robust prediction model is presented.
Abstract: In this paper, two kinds of observer-based sensorless predictive torque control methods are proposed. The predictive method is based on examining feasible voltage vectors (VVs) in a prescribed cost function. The VV that minimizes the cost function is selected. A novel robust prediction model is presented. The prediction model includes sliding mode feedbacks. The feedback gains are assigned by the H-inf method. Two kinds of observers are applied for flux and speed estimation, i.e., sliding mode full order observer and reduced order observer. In order to verify the proposed method, simulation and experimental results are presented in wide speed range. A comparison of the two methods is performed based on the results.
TL;DR: In this paper, a fuzzy sliding mode speed controller with a load torque observer is designed, which can effectively mitigate chattering and guarantee robust speed control of a permanent magnet synchronous motor under model parameter and load torque variations.
Abstract: This paper investigates the robust stabilization problem of a permanent magnet synchronous motor (PMSM). A fuzzy sliding mode speed controller with a load torque observer is designed, which can effectively mitigate chattering and guarantee robust speed control of a PMSM under model parameter and load torque variations. Furthermore, the proposed control method considers the disturbance inputs representing the system nonlinearity or the unmodeled uncertainty. The proposed control algorithm is implemented using a TMS320F28335 floating point DSP. Finally, simulation and experimental results are presented to validate the effectiveness of the proposed scheme.
TL;DR: The experimental results show that the proposed method can still provide accurate SOC estimation when there exist inexact or unknown statistical properties of the errors, and has been applied successfully to the robot for inspecting the running 500-kV extra high voltage power transmission lines.
Abstract: Battery state-of-charge (SOC) estimation is essential for a mobile robot, such as inspection of power transmission lines. It is often estimated using a Kalman filter (KF) under the assumption that the statistical properties of the system and measurement errors are known. Otherwise, the SOC estimation error may be large or even divergent. In this paper, without the requirement of the known statistical properties, a SOC estimation method is proposed using an H∞ observer, which can still guarantee the SOC estimation accuracy in the worst statistical error case. Under the conditions of different currents and temperatures, the effectiveness of the proposed method is verified in the laboratory and field environments. With the comparison of the proposed method and the KF-based one, the experimental results show that the proposed method can still provide accurate SOC estimation when there exist inexact or unknown statistical properties of the errors. The proposed method has been applied successfully to the robot for inspecting the running 500-kV extra high voltage power transmission lines.
TL;DR: In this paper, the Riccati equation approach was used to design a full-order observer for one-sided Lipschitz nonlinear systems, and the reduced-order observers were designed for the same purpose.
TL;DR: The necessary and sufficient conditions for the existence and convergence of the proposed observer are given and proved, and a systemic design approach is presented via the linear matrix inequalities formulation.
TL;DR: It is proved that the proposed control approach can guarantee that all the signals in the closed-loop system are semi-globally uniformly ultimately bounded (SUUB), and both observer error and tracking error can converge to a small neighborhood of the origin.
TL;DR: In this paper, a polytopic Unknown Input Proportional Integral Observer (UIPIO) is proposed for actuator Fault Detection and Isolation (FDI) based on the representation of LPV descriptor systems in polytopic form where its parameters evolve in a hypercube domain.
Abstract: SUMMARY The main contribution of this paper is the design of a polytopic Unknown Input Proportional Integral Observer (UIPIO) for Linear Varying Parameter (LPV) descriptor systems. This observer is used for actuator Fault Detection and Isolation (FDI). The proposed method is based on the representation of LPV descriptor systems in polytopic form where its parameters evolve in a hypercube domain. The designed polytopic UIPIO is also able to estimate the states and the unknown inputs of the LPV descriptor system. Stability conditions of such observer are expressed in terms of Linear Matrix Inequalities (LMI). An example illustrates the performances of such polytopic UIPIO for multiple actuator faults estimation in spite of disturbances. Copyright c 2011 John Wiley & Sons, Ltd.
TL;DR: A new observer synthesis for discrete Takagi-Sugeno (T-S) fuzzy models is designed and it is shown that with a “small” change in the initial Lyapunov function, a ”better” (in the sense of solutions to the linear matrix inequality constraints problem) Lyap unov function can be reached.
Abstract: This paper deals with the design of a new observer synthesis for discrete Takagi-Sugeno (T-S) fuzzy models. It is well established that quadratic synthesis for discrete T-S models and/or linear parameter-varying systems can be outperformed easily via nonquadratic syntheses. Several Lyapunov functions can be used. Nevertheless, this paper shows that with a “small” change in the initial Lyapunov function, a “better” (in the sense of solutions to the linear matrix inequality constraints problem) Lyapunov function can be reached. This one can introduce very important improvements.
TL;DR: An analysis by which the stability of a multiple-input-multiple-output system of simultaneous speed and stator resistance estimators for sensorless induction motor drives can be successfully predicted is presented.
Abstract: This paper presents an analysis by which the stability of a multiple-input-multiple-output system of simultaneous speed and stator resistance estimators for sensorless induction motor drives can be successfully predicted. The instability problem of an adaptive flux observer (AFO) is deeply investigated. In order to achieve stability over a wide range of operation, a design of the observer feedback gain is proposed. Furthermore, closed-loop control systems of the independent use of the two estimators are developed. Therefore, all gains of the adaptive proportional-integral controllers are selected and generalized to provide good tracking performance as well as fast dynamic response. The performance of the AFO using the proposed gains, with a sensorless indirect-field-oriented-controlled induction motor drive, is verified by simulation and experimental results. The results show a good improvement in both convergence and stability, particularly in the regenerative mode at low speeds, which confirm the validity of the proposed analysis.
TL;DR: In this article, the convergence of non-linear extended state observer (ESO) for a class of multi-input multi-output nonlinear systems with uncertainty is studied, where the unknown part that comes from either the system itself or the external disturbance is considered as an augmented state.
Abstract: In this study, the convergence of non-linear extended state observer (ESO) for a class of multi-input multi-output non-linear systems with uncertainty is studied. The unknown part that comes from either the system itself or the external disturbance is considered as an augmented state. The state variable and augmented state are estimated simultaneously through the ESO. It is shown that with the pertinent choice of non-linear functions for observer, the error between the state and observer can be as small as desired when the high-gain tuning parameter is sufficiently small. The current control for permanent-magnet synchronous motor is applied.
TL;DR: The main contribution is to provide some mathematical artifacts on the Lyapunov function to obtain simple and workable stability conditions, furthermore it is shown how to obtain LMI conditions to ensure asymptotic convergence.
TL;DR: It is shown that the pseudo state space representation, usually encountered in the literature for fractional systems, can be used to design Luenberger like observers that permits an estimation of important variables in the system.
TL;DR: In this paper, an output feedback nonlinear control for position tracking of electro-hydraulic systems (EHSs) is proposed, which consists of a high gain observer and a passivity-based controller.
TL;DR: Using continuous frequency distribution, the stability conditions based on indirect approach to Lyapunov stability are derived and a systematic algorithm is presented, which checks for feasibility of a solution to the quadratic inequality and yields an observer whenever the solution is feasible.
TL;DR: In this article, sufficient conditions that ensure the existence of observers for one-sided Lipschitz non-linear systems are established and expressed in terms of linear matrix inequalities (LMIs), which are easily and numerically tractable via standard software algorithms.
Abstract: The one-sided Lipschitz non-linear system is a generalisation of its well-known Lipschitz counterpart and possesses inherent advantages with respect to conservativeness. In this study, the authors deal with the problem of observer design for one-sided Lipschitz non-linear systems by using the linear matrix inequality (LMI) approach. Sufficient conditions that ensure the existence of observers for one-sided Lipschitz non-linear systems are established and expressed in terms of linear matrix inequalities (LMIs), which are easily and numerically tractable via standard software algorithms. It is shown that the proposed conditions are less conservative and more simpler than some existing results in recent literature. Simulation results on two examples are given to illustrate the effectiveness and advantages of the proposed design.
01 Dec 2012
TL;DR: A systematic methodology for designing implicitly verified event-triggered dynamic output feedback controllers for LTI systems that are observable and controllable and it is demonstrated that the triggering conditions provide a global lower bound on the inter-sample times and guarantee asymptotic stability of the closed loop system.
Abstract: In this paper we propose a systematic methodology for designing implicitly verified event-triggered dynamic output feedback controllers for LTI systems that are observable and controllable. Event-triggering conditions that depend only on local information are proposed for sampled-data implementation of the observer and the controller in three different architectures. It is demonstrated that the triggering conditions provide a global lower bound on the inter-sample times and guarantee asymptotic stability of the closed loop system. The proposed design methodology is illustrated through simulation results.
TL;DR: In this article, an observer-based control for fractional-order uncertain linear systems with the fractional commensurate order a (1≤a < 2) based on linear matrix inequality (LMI) approach is presented.
Abstract: The study is concerned with a method of observer-based control for fractional-order uncertain linear systems with the fractional commensurate order a (1≤a<2) based on linear matrix inequality (LMI) approach. First, a sufficient condition for robust asymptotic stability of the observer-based fractional-order control systems is presented. Next, by using matrix's singular value decomposition and LMI techniques, the existence condition and method of designing a robust observer-based controller for such fractional-order control systems are derived. Unlike previous methods, the results are obtained in terms of LMIs, which can be easily obtained by Matlab's LMI toolbox. Finally, a numerical example demonstrates the validity of this approach.
TL;DR: A robust H∞ sliding mode descriptor observer for simultaneous state and disturbance estimation of uncertain system is developed and simulation study illustrates the effectiveness of the proposed method.
Abstract: A robust H∞ sliding mode descriptor observer for simultaneous state and disturbance estimation of uncertain system is developed. Inspired by a singular system theory, a descriptor observer design is presented to estimate some class of output disturbances. A sliding mode scheme is used for the observer to reconstruct the input fault based on the transformed coordinate system. Simulation study illustrates the effectiveness of the proposed method.