Alexey Shumsky

A New Criterion of Fault Estimation for Neutral Delay Systems Using Adaptive Observer

This paper is focused on designing an adaptive observer for a class of neutral-type systems with nonlinear uncertainties. An observer subjected to adaptive law of neutral delay systems with mixed delays and time-varying structured is constructed. Then, the state-estimation-based adaptive law is designed to guarantee the exponentially stability of neutral delay system. Finally, an example is provided to illustrate the efficiency of the proposed method.

A New Criterion of Fault Estimation for Neutral Delay Systems Using Adaptive Observer: A New Criterion of Fault Estimation for Neutral Delay Systems Using Adaptive Observer

This paper studies the problem of fault estimation of neutral delay systems using adaptive observer. A novel fast adaptive fault estimation (FAFE) algorithm based on adaptive observer is first proposed to enhance the performance of fault estimation including rapidity and accuracy. Meanwhile, a delay-dependent criterion is established to reduce the conservatism of design procedures especially for small delay systems. Then, comprehensive analysis is presented to discuss the calculating steps using linear matrix inequality (LMI) technique. Finally, simulation results are presented to illustrate the efficiency of the proposed algorithm.

DATA DRIVEN METHOD FOR FAULT DETECTION AND ISOLATION IN NONLINEAR UNCERTAIN SYSTEMS

Abstract The problem of fault detection and isolation is studied for critical purpose systems whose features are nonlinearities and uncertainties. Solution of the problem assumes the checking redundancy relations existing among measured system inputs and outputs. A novel method is proposed for constructing redundancy relations on the base of system model described by differential equations whose right-hand side is polynomial. The method involves nonlinear transformation of the initial system model into strict feedback form. Algebraic and geometric approaches are used for this transformation. Application of the method is demonstrated for motion model of autonomous underwater vehicle.

FAULT DIAGNOSIS OF SENSORS IN AUTONOMOUS UNDERWATER VEHICLE: ADAPTIVE QUASI-LINEAR PARITY RELATIONS METHOD

Abstract The problem of sensors fault diagnosis in autonomous underwater vehicles is studied within the scope of model-based approach. Adaptive quasi-linear parity relations are considered for solving this problem in the presence of unknown add mass. Simulation results are given for the model of CR-01 autonomous underwater vehicle.

Domino Staudinger/aza-Wittig/Mannich Reaction: an Approach to Diversity of Di- and Tetrahydropyrrole Scaffolds

A highly efficient and selective domino reaction producing valuable di- and tetrahydropyrrole-based skeletons from azidoethyl-substituted CH-acids and (thio)carbonyl compounds has been developed. By involving the additional functional groups in starting compounds into the domino reaction or postmodification of the primary reaction products, the simple construction of the pharmaceutically relevant three- and polycyclic azaheterocyclic scaffolds was demonstrated.

Lewis Acid Triggered Vinylcyclopropane–Cyclopentene Rearrangement

We report a mild Lewis acid induced isomerization of donor-acceptor cyclopropanes, containing an alkenyl moiety and diverse electron-withdrawing group(s) at the adjacent positions, into substituted cyclopentenes. We have found that 1,1,2-trisubstituted cyclopent-3-enes were exclusively obtained in yield of 51-99% when cyclopropanes with a 2-substituted alkenyl group as a donor underwent isomerization. For cyclopropanes bearing a trisubstituted alkenyl group either the corresponding cyclopent-3-enes or isomeric cyclopent-2-enes having two acceptor groups at the C(1) atom were formed, with the reaction selectivity being determined by the applied Lewis acid. We have shown that the reactivity of the donor-acceptor cyclopropane increases with the increase of the electron-donating character of (hetero)aromatic group attached to the alkenyl moiety. The synthetic utility of the developed methodology was also demonstrated through the synthesis of polysubstituted cyclopentane and piperidine derivatives.

Synthesis of hexahydropyridazin-3-ones by reactions between donor-acceptor cyclopropanes and phenylhydrazine

The nickel perchlorate-initiated reaction between dimethyl esters of 2-aryl- and 2-styryl-substituted cyclopropane-1,1-dicarboxylic acids and phenylhydrazine proceeded with opening of the cyclopropane ring and formation of a mixture containing acyclic and cyclic products: [2-(1-phenylhydrazinyl)alkyl]malonates and 1-phenylhexahydropyridazin-3-ones. Reaction conditions were found for preparative synthesis of polyfunctional hexahydropyridazin-3-ones. Unlike the other starting materials, 2-(p-methoxystyryl)-substituted cyclopropane reacted with the terminal NH2 group of phenylhydrazine, resulting in the formation of 1-(phenylamino)pyrrolidin-2-one.

Fault Detectability and Isolability for Nonlinear Uncertain Systems

Abstract This paper considers the detectability and isolability properties of non-linear uncertain systems, by means of tools based on the algebra of functions. Weak and strong properties are introduced, and conditions are given for testing these properties. Constructive procedures are provided to help the calculation of parametric invariants used in the tests. Upper bounds are estimated for the minimal size of detectable and isolable faults.

Quasi-Linear Parity Relations for Fault Detection in Nonlinear Uncertain Systems

Abstract The problem of robust residual generation for fault detection in nonlinear systems is studied within the scope of parity relation approach. The method is proposed for residual generation involving on-line construction of parity relations in quasi-linear form via solution of optimization and time-delay state estimation problems. A nonlinear forced-motion model of underwater vehicle is used to illustrate the robust residual generation and appropriate simulation results are given.

Sensor location for fault accommodation problem

The problem of sensor location for fault accommodation problem in nonlinear dynamic systems is considered. Solution of the problem is related to constructing the control law which provides full decoupling with respect to fault effects. The logic-dynamic approach is used to solve the problem. The main features of this approach are: it involves known linear methods that results in possibility to solve the fault accommodation problem by existing programming systems without using the symbolic software and it can be applied both to discrete-time and continuous-time systems. Existing conditions are formulated and calculating relations are given for the control law. Theoretical results are illustrated by example.