Decentralized observer-based optimal control using two-point boundary value successive approximation approach application for a multimachine power system

In this paper, we present a new decentralized observer for a class of nonlinear interconnected systems, based on an optimal control law using the two-point boundary value (TPBV) successive approximation approach. This technique, used previously to develop a nonlinear decentralized suboptimal control for a multimachine power system, inspired us to develop a new method to design a decentralized observer-based suboptimal control law for the same system. The TPBV approach is characterized by the transformation of each high order coupling nonlinear TPBV problem into a sequence of linear decoupling TPBV problems that uniformly converge to the optimal control for nonlinear interconnected large-scale systems. Sufficient conditions for the asymptotic stability of the developed feedback control scheme are proposed in terms of linear matrix inequalities (LMIs) constraints, which can be efficiently solved by the LMI optimization techniques, to compute the control and the observation gains of the overall system. We applied this approach to a three-machine power system which generators are nonlinear systems strongly interconnected. We demonstrated clearly, via advanced simulations, that this approach was able to bring good performances, improving effectively transient stability of this power system in few iterative sequences while allowing the reconstruction of its non-measurable state variables.

Adaptive Control Design for Nonlinear Systems via Successive Approximations

The paper presents an approach to the Model Reference Adaptive Control (MRAC) design for nonlinear dynamical systems. A nonlinear reference system is considered such that its response is designed to be stable via Successive Approximation Approach (SAA). Having designed the stable reference model through the SAA, MRAC is then formulated for nonlinear plant dynamics with a new adaptation rule to guarantee the convergence of the nonlinear plant response to that of the response of the nonlinear reference model. The proposed design methodology is illustrated with examples for different case studies.

Optimal Disturbances Rejection Control for Autonomous Underwater Vehicles in Shallow Water Environment

To deal with the disturbances of wave and current in the heading control of Autonomous Underwater Vehicles (AUVs), an optimal disturbances rejection control (ODRC) approach for AUVs in shallow water environment is designed to realize this application. Based on the quadratic optimal control theory, the AUVs heading control problem can be expressed as a coupled two-point boundary value (TPBV) problem. Using a recently developed successive approximation approach, the coupled TPBV problem is transformed into solving a decoupled linear state equation sequence and a linear adjoint equation sequence. By iteratively solving the two equation sequences, the approximate ODRC law is obtained. ALuenbergerobserver is constructed to estimate wave disturbances. Simulation is provided to demonstrate the effectiveness of the presented approach.

INTEGRATED ANALOGIC FILTER TUNING SYSTEM DESIGN / INTEGRINIŲ ANALOGINIŲ FILTRŲ SAVAIMINIO DERINIMO SISTEMOS PROJEKTAVIMAS

Parameters of integrated analog filters can vary due to temperatu-re change, IC process variation and therefore they should have dedicated tuning circuits that compensate these imperfections. A method is proposed that speeds up switched resistor bank design while taking into account the required tuning range and step size. A novel counter structure is used in the tuning circuit that is ba-sed on successive approximation approach. The proposed swit-ched resistor design method and tuning circuit are designed in 0.18 μm CMOS technology and verified. Results are compared to existing tuning circuit designs. Integrinių analoginių filtrų parametrai gali kisti dėl temperatūros, senėjimo ar integrinių grandynų gamybos procesų netolydumo. Todėl jiems būtina numatyti papildomus grandynus, kurie kompensuotų filtrų komponentų pokyčius. Darbe siūlomas naujas integrinių aktyviųjų RC filtrų perjungiamų rezistorių matricų projektavimo metodas, kuris leidžia kompensuoti pasyvių komponentų nuokrypius ir užtikrina filtro praleidžiamų dažnių juostos derinimą reikiamu žingsniu. Savaiminio derinimo sistemoje remiamasi nauja skaitiklio architektūra, kuri naudoja nuosekliosios aproksimacijos paieškos algoritmą. Darbe pasiūlytas projektavimo metodas tikrinamas projektuojant filtro derinimo sistemą, naudojant 0,18 μm KMOP integrinių grandynų gamybos technologiją ir Cadence Virtuoso programinę įrangą. Gauti rezultatai palyginami su literatūroje pateiktais derinimo sistemų skaičiavimų rezultatais.

Congestion Control for Nonlinear TD-SCDMA Discrete Networks Based on TCP/IP

A successive approximation approach (SAA) is developed to obtain a new congestion controller for the nonlinear TD-SCDMA network control systems based on TCP/IP. By using the successive approximation approach, the original optimal control problem is transformed into a sequence of nonhomogeneous linear two-point boundary value (TPBV) problems. The optimal control law obtained consists of an accurate linear feedback term and a nonlinear compensation term that is the limit of the solution sequence of the adjoint vector differential equations. By using the finite-time iteration of nonlinear compensation term of optimal solution sequence, we can obtain a suboptimal control law for TD-SCDMA network control systems based on TCP/IP.