geometric polar tracking from bearings only and doppler bearing measurements bearings only tracking bot and doppler bearing tracking dbt perform target motion analysis from measurements of bearings doppler and bearings respectively the state equations are simple for both the target and observer in the rectangular coordinates hence bot and dbt mostly work in that coordinate by developing the trigonometric relations between target and observer postions over time this paper first derives the pseudolinear equations for direct range and bearing estimation it then provides a generalized total least squares gtls and a maximum likelihood solution polar tracking has two advantages over rectangular first for applications that require range and bearing polar output avoids a coordinate conversion at every output instant second polar equations often have a smaller bias than rectangular consequently polar estimates can give a closer to the optimum initialization for iterative algorithms simulation results have validated the theoretical development confirming the near optimality of the gtls and maximum likelihood solutions

an asymptotically unbiased estimator for bearings only and doppler bearing target motion analysis bearings only bo and doppler bearing db target motion analysis tma attempt to obtain a target trajectory based on bearings and on doppler and bearing measurements respectively from an observer to the target the bo tma and db tma problems are nontrivial because the measurement equations are nonlinearly related to the target location parameters the pseudolinear formulation provides a linear estimator solution but the resulting location estimate is biased the instrumental variable method and the numerical maximum likelihood approach can eliminate the bias their convergence behavior however is not easy to control this paper proposes an asymptotically unbiased estimator of the tracking problem the proposed method applies least squares minimization on the pseudolinear equations with a quadratic constraint on the unknown parameters the resulting estimator is shown to be solving the generalized eigenvalue problem the proposed solution does not require initial guesses and does not have convergence problems sequential forms of the proposed algorithms for both bo tma and db tma are derived the sequential algorithms improve the estimation accuracy as a new measurement arrives and do not require generalized eigenvalue decomposition for solution update the proposed estimator achieves the cramer rao lower bound crlb asymptotically for gaussian noise before the thresholding effect occurs

bias reduction for an explicit solution of source localization using tdoa this paper proposes two methods to reduce the bias of the well known algebraic explicit solution chan and ho a simple and efficient estimator for hyperbolic location ieee trans signal process vol 42 pp 1905 1915 aug 1994 for source localization using tdoa bias of a source location estimate is significant when the measurement noise is large and the geolocation geometry is poor bias also dominates performance when multiple times of independent measurements are available such as in uwb localization or in target tracking the paper starts by deriving the bias of the source location estimate from chan and ho the bias is found to be considerably larger than that of the maximum likelihood estimator two methods called biassub and biasred are developed to reduce the bias the biassub method subtracts the expected bias from the solution of chan and ho s work where the expected bias is approximated by the theoretical bias using the estimated source location and noisy data measurements the biasred method augments the equation error formulation and imposes a constraint to improve the source location estimate the biassub method requires the exact knowledge of the noise covariance matrix and biasred only needs the structure of it analysis shows that both methods reduce the bias considerably and achieve the crlb performance for distant source when the noise is gaussian and small the biassub method can nearly eliminate the bias and the biasred method is able to lower the bias to the same level as the maximum likelihood estimator the biasred method is extended for tdoa and fdoa positioning simulations corroborate the performance of the proposed methods

brief an analysis and design method for linear systems subject to actuator saturation and disturbance we present a method for estimating the domain of attraction of the origin for a system under a saturated linear feedback a simple condition is derived in terms of an auxiliary feedback matrix for determining if a given ellipsoid is contractively invariant this condition is shown to be less conservative than the existing conditions which are based on the circle criterion or the vertex analysis moreover the condition can be expressed as linear matrix inequalities lmis in terms of all the varying parameters and hence can easily be used for controller synthesis this condition is then extended to determine the invariant sets for systems with persistent disturbances lmi based methods are developed for constructing feedback laws that achieve disturbance rejection with guaranteed stability requirements the effectiveness of the developed methods is illustrated with examples

on the geometry of a siegel modular threefold introduction 317 1 compactifications 318 2 humbert surfaces 324 3 the chern numbers of s n 331 4 symmetric quartic threefolds 334 5 the modular threefold of level 2 335 6 kummer surfaces 338 7 prym surfaces 340 8 humbert surfaces again 345

dynamic output feedback h control synthesis for discrete time t s fuzzy systems via switching fuzzy controllers this paper studies the problem of dynamic output feedback h control of discrete time takagi sugeno t s fuzzy systems via a switched dynamic parallel distributed compensation dpdc scheme the considered switched dpdc control structure is determined based on the values of membership functions some new properties of membership functions are obtained and exploited to derive sufficient conditions for designing switching dpdc controllers that guarantee the stability and h performances of closed loop nonlinear systems the design conditions are given in terms of solvability of a set of linear matrix inequalities lmis it is shown that the new approach provides results at least as good as the corresponding dpdc methods a numerical example is given to illustrate the effectiveness of the proposed approach

3d pseudolinear target motion analysis from angle measurements the paper presents a new pseudolinear estimator for 3d target motion analysis by a single moving ownship collecting azimuth and elevation angle measurements the 3d pseudolinear estimator is derived as a small noise approximation to the maximum likelihood estimator and consists of a 2d pseudolinear estimator for the xy components of the target motion parameters and a least squares estimator for the z component to improve the poor bias performance of the 3d pseudolinear estimator alternative estimators are proposed employing bias compensation and weighted instrumental variables a selective angle measurement implementation of weighted instrumental variables is presented to maintain a strong correlation between the instrumental variable matrix and the data matrix in the presence of large measurement noise the performance advantages of the selective angle measurement weighted instrumental variable estimator over the conventional maximum likelihood estimator are demonstrated via simulation examples

on the two gap locus for the elliptic calogero moser model we give an analytical description of the locus of the two gap elliptic potentials associated with the corresponding flow of the calogero moser system we start with the description of treibich verdier two gap elliptic potentials the explicit formulae for the covers wavefunctions and lame polynomials are derived together with a new lax representation for the particle dynamics on the locus we then consider more general potentials within the weierstrass reduction theory of theta functions to lower genera the reduction conditions in the moduli space of the genus 2 algebraic curves are given this is a subvariety of the humbert surface which can be singled out by the condition of the vanishing of some theta constants

an antiwindup approach to enlarging domain of attraction for linear systems subject to actuator saturation the article considers linear systems subject to actuator saturation an antiwindup technique is used to enlarge the domain of attraction of the closed loop system under an a priori designed linear dynamic feedback law the design of the antiwindup compensation gain is formulated and solved as an iterative optimization problem with lmi constraints numerical examples are used to demonstrate the effectiveness of the proposed design technique

robust h control for uncertain fuzzy systems with distributed delays via output feedback controllers this paper investigates the problem of robust h output feedback control for a class of uncertain fuzzy systems with distributed delays the system is described by a state space takagi sugeno fuzzy model with distributed delays and norm bounded parameter uncertainties the aim is to design a fuzzy dynamic output feedback controller which ensures the robust asymptotic stability of the closed loop system and guarantees an h norm bound constraint on disturbance attenuation for all admissible uncertainties in terms of linear matrix inequalities a sufficient condition for the solvability of this problem is presented finally simulation examples are provided to illustrate the effectiveness of the proposed design approach

delay dependent guaranteed cost control for t s fuzzy systems with time delays this study introduces a guaranteed cost control method for nonlinear systems with time delays which can be represented by takagi sugeno t s fuzzy models with time delays the state feedback and generalized dynamic output feedback approaches are considered the generalized dynamic output feedback controller is presented by a new fuzzy controller architecture which is of dual indexed rule base it considers both the dynamic part and the output part of t s fuzzy model which guarantees that the controller without any delay information can stabilize time delay t s fuzzy systems based on delay dependent lyapunov functional approach some sufficient conditions for the existence of state feedback controller are provided via parallel distributed compensation pdc first second the corresponding conditions are extended into the generalized dynamic output feedback closed loop system via so called generalized pdc technique the upper bound of time delay can be obtained using convex optimization such that the system can be stabilized for all time delays whose sizes are not larger than the bound the minimizing method is also proposed to search the suboptimal upper bound of guaranteed cost function the effectiveness of the proposed method can be shown by the simulation examples

elliptic genera of toric varieties and applications to mirror symmetry the paper contains a proof that elliptic genus of a calabi yau manifold is a jacobi form finds in which dimensions the elliptic genus is determined by the hodge numbers and shows that elliptic genera of a calabi yau hypersurface in a toric variety and its mirror coincide up to sign the proof of the mirror property is based on the extension of elliptic genus to calabi yau hypersurfaces in toric varieties with gorenstein singularities

bias compensation for the bearings only pseudolinear target track estimator the bearings only pseudolinear target track estimator is known to suffer from severe bias problems this paper presents a bias analysis for the pseudolinear estimator and develops a method of bias compensation resulting in a closed form reduced bias pseudolinear estimator the reduced bias estimator is then incorporated into an instrumental variable estimator to produce asymptotically unbiased target motion parameter estimates unlike batch iterative estimators the proposed instrumental variable estimator has a closed from solution and therefore avoids the convergence problems associated with iterative estimators the performance of the proposed instrumental variable estimator is illustrated by way of simulation examples and is shown to be almost identical to that of the computationally more demanding iterative maximum likelihood estimator

robust stability analysis and fuzzy scheduling control for nonlinear systems subject to actuator saturation takagi sugeno ts fuzzy models can provide an effective representation of complex nonlinear systems in terms of fuzzy sets and fuzzy reasoning applied to a set of linear input output submodels in this paper the ts fuzzy modeling approach is utilized to carry out the stability analysis and control design for nonlinear systems with actuator saturation the ts fuzzy representation of a nonlinear system subject to actuator saturation is presented in our ts fuzzy representation the modeling error is also captured by norm bounded uncertainties a set invariance condition for the system in the ts fuzzy representation is first established based on this set invariance condition the problem of estimating the domain of attraction of a ts fuzzy system under a constant state feedback law is formulated and solved as a linear matrix inequality lmi optimization problem by viewing the state feedback gain as an extra free parameter in the lmi optimization problem we arrive at a method for designing state feedback gain that maximizes the domain of attraction a fuzzy scheduling control design method is also introduced to further enlarge the domain of attraction an inverted pendulum is used to show the effectiveness of the proposed fuzzy controller

a novel batch bayesian wiv estimator for three dimensional tma using bearing and elevation measurements in this paper we derive a novel batch bayesian weighted instrumental variable estimator for the three dimensional 3d target motion analysis tma problem using bearing and elevation measurements unlike most existing 3d estimators based on instrumental variables the proposed approach is able to incorporate a priori information into the estimation process and is proven to be approximately asymptotically unbiased an approximate asymptotic covariance matrix is also presented to evaluate the performance of the estimator simulation results show that the proposed estimator outperforms its non bayesian counterpart and has an estimation performance on par with the conventional iterative maximum a posteriori estimator while being orders of magnitude faster in a passive sonar tma problem moreover it was shown that the proposed approach can provide an accurate initialization for recursive estimators

robust anti windup controller design of time delay fuzzy systems with actuator saturations this study presents a robust anti windup fuzzy control approach for uncertain nonlinear time delay systems with actuator saturations the discussed system dynamics is presented by the takagi sugeno t s fuzzy model to facilitate the design process the nonlinearity of input saturation is characterized by a specific sector condition given a stabilizing dynamic output feedback fuzzy controller an anti windup control approach is then developed to maximize the size of estimate of the domain of attraction significantly the convergence of all admissible initial states within this region could be ensured based on the lyapunov krasovskii delay independent and delay dependent analyses sufficient conditions for the robust stabilization are derived these conditions are formulated as a convex optimization problem with constraints represented by a set of linear matrix inequalities allowing the fuzzy controller to be synthesized more efficiently finally numeric simulations are given to validate the proposed approach

an anti windup design for linear systems with input saturation abstract an anti windup design problem is posed and it is shown that all observer based anti windup modifications solve this problem at least locally sufficient conditions for an observer based anti windup modification to solve the global version of this problem are presented a novel observer based anti windup design is then proposed such that the anti windup problem can be interpreted in terms of a reduced order system in particular the proposed anti windup design induces an invariant subspace for the dynamic behavior of the mismatch between the constrained and unconstrained closed loops the dynamics in this invariant subspace are identical to the behavior of the plant with input saturation starting at the origin stabilized by linear state feedback and driven by the mismatch between the unconstrained input and this input passed through a saturation function the second part of the paper shows how the original dynamic compensator can be modified while retaining those dynamic features that produce a desirable closed loop steady state response to ensure that the requisite invariant subspace exists and it is reasonably tuned for input saturation two case studies are carried out on systems that have been investigated in the literature

efficient closed form algorithms for aoa based self localization of sensor nodes using auxiliary variables node self localization is a key research topic for wireless sensor networks wsns there are two main algorithms the triangulation method and the maximum likelihood ml estimator for angle of arrival aoa based self localization the ml estimator requires a good initialization close to the true location to avoid divergence while the triangulation method cannot obtain the closed form solution with high efficiency in this paper we develop a set of efficient closed form aoa based self localization algorithms using auxiliary variables based methods first we formulate the self localization problem as a linear least squares problem using auxiliary variables based on its closed form solution a new auxiliary variables based pseudo linear estimator avple is developed by analyzing its estimation error we present a bias compensated avple bcavple to reduce the estimation error then we develop a novel bcavple based weighted instrumental variable bcavple wiv estimator to achieve asymptotically unbiased estimation of locations and orientations of unknown nodes based on prior knowledge of the aoa noise variance in the case that the aoa noise variance is unknown a new avple based wiv avple wiv estimator is developed to localize the unknown nodes also we develop an autonomous coordinate rotation acr method to overcome the tangent instability of the proposed algorithms when the orientation of the unknown node is near 2 we also derive the cramer rao lower bound crlb of the ml estimator extensive simulations demonstrate that the new algorithms achieve much higher localization accuracy than the triangulation method and avoid local minima and divergence in iterative ml estimators

fundamental properties and performance of conventional bearings only target motion analysis this paper considers the problem of estimating the position and velocity of an object from noise corrupted bearing measurements obtained by a single moving observation platform the process is inherently nonlinear and exhibits unusual observability properties that are geometry dependent a maximum likelihood estimate mle of the target motion analysis solution is developed and its performance analyzed a comparison is drawn between the mle and two previously reported methods a nonlinear modified instrumental variable estimate miv and the pseudo linear estimate ple both the miv and ple are shown to derive from approximations to the nonlinear measurement equation and therefore share some common properties with the mle the limits on performance that can be expected from processing bearing data are detailed specifically for long range to baseline geometries approximate expressions for the cramer rao bound are derived extension of the results to the practical filters approximately predicts numerically observed behavior for less restrictive geometries bounds are presented incorporation of a target speed constraint on the mle results in a transition to a lower dimensional problem as noise level and range increases monte carlo experimental results are presented and the improvements realized by the mle techniques are evident

some quick and efficient methods for bearing only target motion analysis batch processing estimation methods for a target s trajectory assumed to be linear and uniform based only on the observation of its bearings are presented first the observer is assumed to have constant velocity so that one can only estimate the target s motion up to a multiplicative constant this motion is parameterized by three bearings at three judiciously chosen times and some simple quick yet highly efficient estimators for them are proposed the case of an observer moving nonuniformly is then considered a quadratic estimator that is similar to the pseudolinear estimator but does not have bias is introduced for the case in which the observer s motion can be decomposed into a finite number of constant velocity segments two sets of quasi sufficient statistics that permit considerable saving in computation with no significant loss of efficiency are also introduced expressions for the covariance matrix of the estimators and for their cramer rao bounds are provided

new approach on robust delay dependent h _ infty control for uncertain t s fuzzy systems with interval time varying delay this paper investigates the robust h infin control for takagi sugeno t s fuzzy systems with interval time varying delay by employing a new and tighter integral inequality and constructing an appropriate type of lyapunov functional delay dependent stability criteria are derived for the control problem because neither any model transformation nor free weighting matrices are employed in our theoretical derivation the developed stability criteria significantly improve and simplify the existing stability conditions also the maximum allowable upper delay bound and controller feedback gains can be obtained simultaneously from the developed approach by solving a constrained convex optimization problem numerical examples are given to demonstrate the effectiveness of the proposed methods

relationship between geometric translations and tls estimation bias in bearings only target localization this paper analyzes the effects of local coordinate translations and rotations on the bias and mean squared error performance of the total least squares tls bearings only target localization algorithm the tls estimator was originally proposed to alleviate the severe bias problems associated with the traditional pseudolinear estimator an interesting property of the tls estimator which is not shared by the pseudolinear estimator is that its bias is sensitive to where the origin of the local cartesian coordinates is placed the paper provides a formal proof of this observation discusses its implication on bias minimization and proposes a simple and effective method for tls bias reduction the findings of the paper are illustrated with comprehensive simulation examples

bearings only target motion analysis via instrumental variable estimation this paper deals with the instrumental variable iv estimation for the problem of target motion analysis from bearing only measurements bo tma by taking asymptotical analysis of the iv estimation a systematic method for developing consistent iv estimate and the sufficient condition for its asymptotical normality are proposed the asymptotical covariance of iv estimate is also derived explicitly which can be used to evaluate its performance these results generalize the previous studies and enhance the application of the iv estimation in target tracking numerical examples are shown to verify the theoretical results

utilization of modified polar coordinates for bearings only tracking previous studies have shown that the cartesian coordinate extended kalman filter exhibits unstable behavior characteristics when utilized for bearings only target motion analysis tma in contrast formulating the tma estimation problem in modified polar mp coordinates leads to an extended kalman filter which is both stable and asymptotically unbiased exact state equations for the mp filter are derived without imposing any restrictions on own ship motion thus prediction accuracy inherent in the traditional cartesian formulation is completely preserved in addition these equations reveal that mp coordinates are well suited for bearings only tma because they automatically decouple observable and unobservable components of the estimated state vector such decoupling is shown to prevent covariance matrix ill conditioning which is the primary cause of filter instability further investigation also confirms that the mp state estimates are asymptotically unbiased realistic simulation data are presented to support these findings and to compare algorithm performance with respect to the cramer rao lower bound ideal as well as the cartesian and pseudolinear filters

output feedback stabilization of linear systems with actuator saturation the note presents a method for designing an output feedback law that stabilizes a linear system subject to actuator saturation with a large domain of attraction this method applies to general linear systems including strictly unstable ones a nonlinear output feedback controller is first expressed in the form of a quasi lpv system conditions under which the closed loop system is locally asymptotically stable are then established in terms of the coefficient matrices of the controller the design of the controller coefficient matrices that maximizes an estimate of the domain of attraction is then formulated and solved as an optimization problem with lmi constraints

antiwindup design with guaranteed regions of stability an lmi based approach this note addresses the design of antiwindup gains for obtaining larger regions of stability for linear systems with saturating inputs considering that a linear dynamic output feedback has been designed to stabilize the linear system without saturation a method is proposed for designing an antiwindup gain that maximizes an estimate of the basin of attraction of the closed loop system it is shown that the closed loop system obtained from the controller plus the antiwindup gain can be modeled by a linear system with a deadzone nonlinearity a modified sector condition is then used to obtain stability conditions based on quadratic lyapunov functions differently from previous works these conditions are directly in linear matrix inequality form some numerical examples illustrate the effectiveness of the proposed design technique when compared with the previous ones

delay dependent robust h sub spl infin control for t s fuzzy systems with time delay this paper focuses on the problem of delay dependent robust fuzzy control for a class of nonlinear delay systems via state feedback the takagi sugeno t s fuzzy model is adopted for representing a nonlinear system with time delayed state a delay dependent stabilization criterion is first presented then the methods of robust stabilization and robust h sub spl infin control are developed which are dependent on the size of the delay and are based on the solutions of linear matrix inequalities lmis finally a design example of robust h sub spl infin controller for uncertain nonlinear systems is given to illustrate the effectiveness of the approaches proposed in this paper

output feedback lmi tracking control conditions with h criterion for uncertain and disturbed t s models this work concerns the tracking problem of uncertain takagi sugeno t s continuous fuzzy model with external disturbances the objective is to get a model reference based output feedback tracking control law the control scheme is based on a pdc structure a fuzzy observer and a h performance to attenuate the external disturbances the stability of the whole closed loop model is investigated using the well known quadratic lyapunov function the key point of the proposed approaches is to achieve conditions under a lmi linear matrix inequalities formulation in the case of an uncertain and disturbed t s fuzzy model this formulation facilitates obtaining solutions through interior point optimization methods for some nonlinear output tracking control problems finally a simulation is provided on the well known inverted pendulum testbed to show the efficiency of the proposed approach

piecewise fuzzy anti windup dynamic output feedback control of nonlinear processes with amplitude and rate actuator saturations in this paper a novel anti windup dynamic output compensator is developed to deal with the robust h infin output feedback control problem of nonlinear processes with amplitude and rate actuator saturations and external disturbances via fuzzy modeling of nonlinear systems the proposed piecewise fuzzy anti windup dynamic output feedback controller is designed based on piecewise quadratic lyapunov functions it is shown that with sector conditions robust output feedback stabilization of an input constrained nonlinear process can be formulated as a convex optimization problem subject to linear matrix inequalities simulation study on a strongly nonlinear continuously stirred tank reactor cstr benchmark plant is given to show the performance of the proposed anti windup dynamic compensator

brief multivariable anti windup controller synthesis using linear matrix inequalities we present a general formulation of the problem of multi variable anti windup bumpless transfer awbt controller synthesis which provides sufficient conditions for stability covering a large class of typical input nonlinearities such as saturation deadzone and switching override nonlinearities the resulting synthesis method demonstrates graceful performance degradation whenever input nonlinearities are active through minimization of a weighted l 2 gain the main contribution of the paper is that the awbt controller synthesis using static compensation is cast as a convex optimization over linear matrix inequalities

on design of dynamic output feedback controller for gcs of large scale systems with delays in interconnections lmi optimization approach this paper considers the dynamic output feedback controller design problem for decentralized guaranteed cost stabilization gcs of large scale systems with time delays in subsystem interconnections based on the lyapunov method a linear matrix inequality lmi convex optimization problem is formulated to find the controller which guarantees the asymptotic stability and minimizes the upper bound of a given quadratic cost function

a novel location penalized maximum likelihood estimator for bearing only target localization in this paper we present a location penalized maximum likelihood lpml estimator for bearing only target localization we develop a new penalized maximum likelihood cost function by transforming the variables of target position and bearings the new penalized likelihood function can also be recognized as a posterior distribution under a bayesian framework by penalizing a prior we give analysis of the asymptotic properties and show that both traditional bearing maximum likelihood tbml and lpml estimators are asymptotically efficient estimators to compare the performances of the tbml and lpml estimators we analyze the cramer rao lower bound crlb of the two estimators and show that the bound of the lpml estimator is lower than that of the tbml estimator extensive simulations are performed it is observed that the new lpml algorithm consistently outperforms other well known algorithms field experiments are also conducted by applying this method to localize a vehicle using real world data acquired by an acoustic array sensor network the new lpml algorithm demonstrates superior performance in all the field experiments

synthesis of controllers for continuous time delay systems with saturating controls via lmis the stabilization of linear continuous time systems with time delay in the state and subject to saturating controls is addressed sufficient conditions obtained via a linear matrix inequality lmi formulation are stated to guarantee both the local stabilization and the satisfaction of some performance requirements the method of synthesis consists in determining simultaneously a state feedback control law and an associated domain of safe admissible states for which the stability of the closed loop system is guaranteed when control saturations effectively occur

a novel closed form estimator for 3d tma using heterogeneous sensors this paper considers the problem of three dimensional target motion analysis using a combination of bearing elevation and time difference of arrival tdoa measurements we propose a hybrid closed form solution based on the weighted instrumental variables for this highly nonlinear problem the proposed solution avoids the high computational complexity and convergence problems associated with iterative estimators furthermore the simulation results suggest that the proposed estimator is nearly efficient since its performance is very close to the best achievable performance as predicted by the cramer rao lower bound

recursive total least squares algorithm based on inverse power method and dichotomous coordinate descent iterations we develop a recursive total least squares rtls algorithm for errors in variables system identification utilizing the inverse power method and the dichotomous coordinate descent dcd iterations the proposed algorithm called dcd rtls outperforms the previously proposed rtls algorithms which are based on the line search method with reduced computational complexity we perform a comprehensive analysis of the dcd rtls algorithm and show that it is asymptotically unbiased as well as being stable in the mean we also find a lower bound for the forgetting factor that ensures mean square stability of the algorithm and calculate the theoretical steady state mean square deviation msd we verify the effectiveness of the proposed algorithm and the accuracy of the predicted steady state msd via simulations

technical communique robust stabilization of uncertain systems with unknown input delay this paper is concerned with the robust controller design for uncertain input delayed systems the time delay is assumed to be an unknown constant a controller with delay feedback for the robust stabilization of the system is proposed the stability criterion of the closed loop system is derived in terms of linear matrix inequalities lmis examples show that in many cases our method can give less conservative results than those by the existing methods moreover for the same cases our controllers have lower feedback gains than the existing ones

robust fuzzy scheduling control for nonlinear systems subject to actuator saturation via delta operator approach this paper focuses on robust fuzzy scheduling control for nonlinear systems with actuation saturation via delta operator approach a class of t s fuzzy delta operator systems is extended to describe nonlinear systems subject to actuator saturation and linear fractional uncertainty moreover a set invariance condition is established for t s fuzzy delta operator systems based on the set invariance condition an optimization approach is proposed to estimate the domain of attraction for the t s fuzzy delta operator systems the domain of attraction is arbitrarily close to a null controllable region by the designed pdc control law or non pdc control law furthermore the non pdc control law is proposed by using fuzzy weighting dependent lyapunov function the effectiveness of the developed techniques is shown through a numerical example

a novel approach for static anti windup compensation of one sided lipschitz systems under input saturation abstract this paper illustrates a new strategy for designing the local static anti windup aw compensator for nonlinear systems with one sided lipschitz osl nonlinearities under saturating actuators and exogenous disturbances the static aw strategy is designed such that the resulting closed loop system with osl nonlinearity actuator saturation and exogenous disturbance is stable and the region of attraction can be maximized inequalities based conditions are formulated for the static aw gain design by using lyapunov stability theory sector condition l2 gain reduction osl inequality and quadratic inner bounded qib condition the proposed aw technique is simpler to design straightforward to implement and deals with a broader class of systems in contrast to conventional methods an application example demonstrates that the proposed static aw can successfully mitigate the saturation consequences in osl nonlinear systems