Zero Steady State Research Articles

Centralization of capital and economic conditions for peace

This paper explores the implications of global capital centralization, defined as increasing ownership of the global capital stock by the dominant economic power. The paper explores a capitalist ‘reproduction’ scheme detailing a ‘zero steady state’ of capital centralization. The scheme examines the links between trade imbalances, capital centralization, and ‘imperialism’ and analyzes how these affect the stability of international relations. The study examines steady state properties as potential ‘economic conditions’ that influence the deterioration or pacification of international political relations.

Tracking Control With Zero Steady State for UAV Flight Platform

Tracking Control With Zero Steady State for UAV Flight Platform

Modeling of Automatic Generation Control and Automatic Voltage Regulator Under Generation Rate Constraint

As the interconnected power system transmits power from one area to another, the frequency will inevitable deviate from scheduled frequency. In addition, the active and reactive power demands continually change with rising and falling trend. Any mismatch between system generation and demand results in change in system frequency that is highly undesired. Excitation of generator must be regulated in order to match the power demand, otherwise the bus voltage may fall beyond the permitted limit. In this paper, a simulation model is developed for each component of AGC and AVR loops considering generator rate constraints. The response with GRC is compared with the analysis done without the Generation Rate Constraint. Although the frequency deviation is less with suitable controllers when the GRC is not considered, it is not the actual frequency deviation. When GRC is considered the actual frequency deviation can be found and then accordingly the controller is tuned. So that the desired frequency and power interchange with neighboring systems are maintained in order to minimize the transient deviations and to provide zero steady state error in appropriate short time. Further the role of automatic voltage control is to maintain the terminal voltage of synchronous generator in order to maintain the bus bar voltage Results are obtained using MATLAB SIMULINK software.

Coupling between Automatic Generation Control and Automatic Voltage Regulator While Considering Generation Rate Constraint of Two Areas

This paper describes the implementation of automatic generation control (AGC) and automatic voltage regulator (AVR) under generation rate constraint (GRC) and coupling between automatic generation control and automatic voltage regulator while considering generation rate constrain of two areas for improve and better performance characteristic of load frequency control (LFC) problem. our control aim has to normalize the area control error (ACE), frequency error and tie-line power error in spite of the presences of system uncertainties and external load disturbance, So that the required frequency and power interchange with adjacent structures are maintained in order to reduce the transient deviations and to provide zero steady state error in proper short time, the behavior of the planned is checked by MATLAB SIMULINK software.

Timing and shape of stochastic autocatalytic burst formation.

Chemical, physical, and ecological systems passing through a saddle-node bifurcation will, momentarily, find themselves balanced at a semistable steady state. If perturbed by noise, such systems will escape from the zero-steady state, with escape time sensitive to noise. When the model is extended to include space, this leads to different points in space "escaping from zero" at different times, and uniform initial conditions nucleate into sharp peaks spreading randomly across a nearly uniform background, a phenomenon closely resembling nucleation during phase transition. We use Large Deviation Theory to determine burst shape and temporal scaling with respect to noise amplitude. These results give a prototype for a particular form of patternless symmetry breaking in the vicinity of a stability boundary and demonstrate how microscopic noise can lead to macroscopic effects in such a region.

Kinetic Instability of Zero Steady State As a Fundamental Cause of Low Efficiency of Chemotherapy of Cancer.

Using mathematical modeling of the process of cancer treatment by the classical chemotherapy methods and therapy with biological agents, the effect of the kinetic parameters of the model on the final outcome of treatment was studied. It is established that the complete cure (i.e., the formation of a stable steady state with a zero number of cancer cells) cannot be reached by means of only classical chemotherapy.

Kinetic Instability of Zero Steady State as a Fundamental Couse of Low Efficiency of Chemiotherapy of Cancer

Kinetic Instability of Zero Steady State as a Fundamental Couse of Low Efficiency of Chemiotherapy of Cancer

IMC based Fractional Order Controller Design for Specific Non-Minimum Phase Systems

Internal model control (IMC) structure is derived from classical control by introducing the model of plant in the control loop and thereby having significant advantages over classical control such as dual stability, perfect control and zero-steady state offset. The basic one degree of freedom (ODF) IMC provides good compromise between set-point tracking and disturbance rejection and works well for non-minimum phase (NMP) systems. In this work, an IMC based fractional order (FO) controller is designed for NMP system which satisfy desired phase margin (ϕm) at a desired gain-crossover frequency (ωg). The domain of desired ϕm and ωg is provided from which they can be selected. Simulation studies are done for (i) DC-DC boost converter which is a NMP system with one zero in right half of s-plane and (ii) first order plus time delay (FOPTD) system which is also a NMP system because of the delay. Significance of the proposed methodology is verified by comparing with other well-known techniques in IMC based on the performance measures, such as rise time (Tr), settling time (Ts) and overshoot (%Mp) and performance indices such as integral square error (ISE), integral absolute error (IAE) and integral of the time weighted absolute error (ITAE).

English

English

Predictive control strategies for wind turbine system based on permanent magnet synchronous generator

In this paper, Model Predictive Control and Dead-beat predictive control strategies are proposed for the control of a PMSG based wind energy system. The proposed MPC considers the model of the converter-based system to forecast the possible future behavior of the controlled variables. It allows selecting the voltage vector to be applied that leads to a minimum error by minimizing a predefined cost function. The main features of the MPC are low current THD and robustness against parameters variations. The Dead-beat predictive control is based on the system model to compute the optimum voltage vector that ensures zero-steady state error. The optimum voltage vector is then applied through Space Vector Modulation (SVM) technique. The main advantages of the Dead-beat predictive control are low current THD and constant switching frequency. The proposed control techniques are presented and detailed for the control of back-to-back converter in a wind turbine system based on PMSG. Simulation results (under Matlab-Simulink software environment tool) and experimental results (under developed prototyping platform) are presented in order to show the performances of the considered control strategies.

Dynamic model of proximity of positions of social network users

A mathematical model is proposed for the proximity dynamics of political positions of interacting individuals which form a closed group. The model is described as a system of ordinary differential equations. The results of numerical experiments for the system are presented and a number of substantial conclusions are formulated. It is shown that in the case of two individuals the system has an asymptotically stable zero steady state. In the case of two individuals and two themes we get an infinite number of stationary states, all except the zero state being unstable.

Entry of firms and cost of disinflation in New Keynesian models

Introducing costs of entry in the product market into a New Keynesian model with Calvo-type price setting and non zero steady state inflation is a means to restore output costs of disinflation in the short run, before output gains in the long run.

Determining maximum load-carrying capacity of robots using adaptive robust neural controller

SUMMARYIn this paper, the combination of neural network (NN), proportional derivative (PD), and robust controller are used for determining the maximum load-carrying capacity (MLCC) of articulated robots, subject to both actuator and end-effector deflection constraints. The proposed technique is then applied to articulated robots, and MLCC is obtained for a given trajectory. In the practical simulations, it's impossible to determine the parameters of robot model exactly, so the trajectory tracking performance of the proportional integral derivative (PID) and computed torque methods significantly decrease. The PD control of robot has major problem, it cannot guarantee zero steady state error. For this reason, the NN controller with PD and robust controller are used. The multilayer neural network is also used to compensate gravity and friction effects. By using Lyapunov Direct Method it is shown that the stability of closed loop system would be guaranteed, if the weights of multilayer had certain learning rules. Standard back propagation algorithm is used as a learning algorithm to update the connection weights of the NN controller. The simulation results of the proposed adaptive robust neural network (ARNN) controller are compred with sliding mode and feedback linearization methods for flexible joint robot, and compared with open loop controller for 3D industrial robot. The obtained results assured the robustness and improvement in MLCC in the presence of uncertainties in dynamic model of the robot arm and external disturbances. In fact, adaptive robust NN controller suppresses disturbances accurately and achieves very small errors between commanded and actual trajectories.

Methods for determination and approximation of the domain of attraction in the case of autonomous discrete dynamical systems

A method for determination and two methods for approximation of the domain of attraction D a (0) of the asymptotically stable zero steady state of an autonomous, ℝ-analytical, discrete dynamical system are presented. The method of determination is based on the construction of a Lyapunov function V, whose domain of analyticity is D a (0). The first method of approximation uses a sequence of Lyapunov functions V p , which converge to the Lyapunov function V on D a (0). Each V p defines an estimate N p of D a (0). For any x ∈ D a (0), there exists an estimate which contains x. The second method of approximation uses a ball B(R) ⊂ D a (0) which generates the sequence of estimates M p = f-p(B(R)). For any x ∈ D a (0), there exists an estimate which contains x. The cases ||∂0f||<1 and ρ(∂0f) < 1 ≤||∂0f|| are treated separately because significant differences occur.

Methods for determination and approximation of the domain of attraction

In this paper, an R -analytical function and the sequence of its Taylor polynomials (which are Lyapunov functions different from those of Vanelli and Vidyasagar (Automatica 21(1) (1985) 69–80)) is presented, in order to determine and approximate the domain of attraction of the exponentially asymptotically stable zero steady state of an autonomous, R -analytical system of differential equations. The analytical function and the sequence of its Taylor polynomials are constructed by recurrence formulae using the coefficients of the power series expansion of f at 0.

CAutoCSD-evolutionary search and optimisation enabled computer automated control system design

This paper attempts to set a unified scene for various linear time-invariant (LTI) control system design schemes, by transforming the existing concept of “computer-aided control system design” (CACSD) to novel “computer-automated control system design” (CAutoCSD). The first step towards this goal is to accommodate, under practical constraints, various design objectives that are desirable in both time and frequency domains. Such performance-prioritised unification is aimed at relieving practising engineers from having to select a particular control scheme and from sacrificing certain performance goals resulting from pre-commitment to such schemes. With recent progress in evolutionary computing based extra-numeric, multi-criterion search and optimisation techniques, such unification of LTI control schemes becomes feasible, analytical and practical, and the resultant designs can be creative. The techniques developed are applied to, and illustrated by, three design problems. The unified approach automatically provides an integrator for zero-steady state error in velocity control of a DC motor, and meets multiple objectives in the design of an LTI controller for a non-minimum phase plant and offers a high-performance LTI controller network for a non-linear chemical process.

Bloch oscillations in a Boltzmann transport equation formalism under the relaxation time approximation

We derive the Bloch oscillation currents in a semicondctor superlattice from a Boltzmann transport equation approach, in the relaxation time approximation. The zero temperature time dependent current obtained when a constant uniform electric field F is applied along the superlattice axis has two contributions: (a) a large transient current which clearly shows oscillations at the Bloch frequency eFd h ̵ , where d is the superlattice period and (b) an initially smaller, out of phase oscillating current which eventually becomes the non zero steady state contribution. Depending on the magnitude of the electric field, the steady state component may be an order of magnitude smaller than the initial amplitude of the oscillating current. The current-voltage characteristics of the steady state component recovers the well known negative differential conductivity as originally established by Esaki Tsu.

Molecular dynamics studies of the role of diffusion in chemical models with absorbing boundary states

Molecular dynamic studies show that in chemical models with absorbing zero boundary states fast diffusion stabilizes the deterministic non zero steady state, whereas slow diffusion favors extinction.