Active Disturbance Rejection Control for Uncertain Nonlinear Systems With Sporadic Measurements

This paper deals with the problem of active disturbance rejection control(ADRC)design for a class of uncertain nonlinear systems with sporadic measurements.A novel extended state observer(ESO)is designed in a cascade form consisting of a continuous time estimator,a continuous observation error predictor,and a reset compensator.The proposed ESO estimates not only the system state but also the total uncertainty,which may include the effects of the external perturbation,the parametric uncertainty,and the unknown nonlinear dynamics.Such a reset compensator,whose state is reset to zero whenever a new measurement arrives,is used to calibrate the predictor.Due to the cascade structure,the resulting error dynamics system is presented in a non-hybrid form,and accordingly,analyzed in a general sampled-data system framework.Based on the output of the ESO,a continuous ADRC law is then developed.The convergence of the resulting closed-loop system is proved under given conditions.Two numerical simulations demonstrate the effectiveness of the proposed control method.

Stochastic bounded consensus tracking of leader-follower multi-agent systems with measurement noises based on sampled data with general sampling delay

In this paper we provide a unified framework for consensus tracking of leader-follower multi-agent systems with measurement noises based on sampled data with a general sampling delay. First, a stochastic bounded consensus tracking protocol based on sampled data with a general sampling delay is presented by employing the delay decomposition technique. Then, necessary and sufficient conditions are derived for guaranteeing leader-follower multi-agent systems with measurement noises and a time-varying reference state to achieve mean square bounded consensus tracking. The obtained results cover no sampling delay, a small sampling delay and a large sampling delay as three special cases. Last, simulations are provided to demonstrate the effectiveness of the theoretical results.

Multi-Aspect Value of Measuring Systems and Methods Based on the Results of Roundness Measurements

The increase of quality consciousness brings about the growth of significance of metrological systems. Besides the significance, the level of automatization, flexibility, accuracy, et al. have advanced. The modern measuring systems are constructed so that nearly all necessary dimensional characteristics can be measured with them. However, conventional measuring systems are provided for particular mode measurements. This research paper presents and compares several conventional and modem measuring systems and methods. The measured value is roundness, one of the basic shapes of cross section in mechanical engineering. This paper arises in search of answers for the question whether conventional measuring techniques and equipments are made redundant because of the modern ones. In what segments and in which criterion are modem methods preferable？

The Analysis of Systems of Measurement for the Construction of Geometrical Models of the Product

In the present work,the relevant components of the two basic system of measurement are defined through the analysis of existing systems of measurement for geometrical modeling.The major features of such systems related to the ways of formation of the two-dimensional complex drawing of a geometrical image on the basis of laws of projective connections are revealed.Interrelations of the elements of different systems of measurement with various projections of a geometrical image are defined.The relative location of projections of a geometrical image into the constructed two-dimensional complex drawings for various systems of measurement is discussed.The rationale behind a particular arrangement of views in the projective drawing of a product in the analyzed systems of measurement is explained.

Partial Discharge Measurement of OCP-Tapes in Rotating Electrical Machines

Nowadays, PD （partial discharge） measurements are a crucial part of the preventive maintenance of electrical equipment within high voltage engineering. Especially for electrical machines, both the supplier and the user are interested in the results of PD measurements. However, PDs hardly represent the cause of the failure, more likely they are claimed as the outcome of a failure. This paper deals with the insulation of a 6 kV electrical machine, whereas PD measurements were carried out at a single stator from wound coils. During manufacturing, these coils were equipped with different materials for the OCP （outer corona protection）. Using different PD measurement systems and different bandwidths, investigations of the PD behavior of the coils were carried out. Additionally, the surface resistivity of the corona protection was determined. As a result, conclusions for the correlations between the resistance of the OCP as well as the PD behavior are stated. Furthermore, the influence of using different measurement systems, different measuring circuits, and different bandwidths is shown.

INITIAL-OBLIQUE DERIVATIVE PROBLEMS FOR NONLINEAR PARABOLIC SYSTEMS WITH MEASURABLE COEFFICIENTS

This paper deals with some initial-oblique derivative boundary value problems for nonlinear nondivergent parabolic systems of several second order equations with measurable coefficients in multiply connected domains. Firstly, a priori estimates of solutions for the initial-boundary value problems are given, and then by using the above estimates of solutions and the Leray-Schauder theorem, the existence and uniqueness of solutions for the problems are proved.

RESIDUAL GAS IONIZATION BEAM PROFILE MONITOR ON 40MeV H^— BEAM TRANSPORT LINE

The monitor is composed of a pair of electrodes,a single stage of microchannel plate,a phosphor screen,a CCD camera and a PC computer,To obtain a good uniform collecting field,forming electrodes system is used instead of that with a resistive divider,The readout system is performed by the phosphor screen and the CCD camera because the spatial resolution is not limited by the mechanical structure like the anode strip type and such video display system is very useful for beam studies and operation of the 40MeV linac,Besides,the design and test results are described in detail.

Wireless measurement of orthodontic forces in invisible aligners

Invisible orthodontic treatment is an effective form of malocclusion treatment favored in recent years.The magnitude of its orthodontic force has a crucial impact on the outcome of the treatment and has gained a high level of clinical interest.However,there are very few explorations of in vivo measurements of orthodontic force,and existing studies are limited to a large number of couplings,which are inconvenient for clinical use.In this work,we developed a wireless flexible measurement system that allows quantitative measurement of the orthodontic force of an invisible aligner on a dental model.The system is wireless,tiny,flexible,fast responding,and has a range suitable for the range of orthodontic forces.We show the difference in the orthodontic force applied to different tooth positions and the difference in the orthodontic force applied to different positions of the same tooth.In addition,the system can evaluate the mechanical differences between aligners of different brands and materials as well as the deviation of fabrication results.This system provides a test tool and evaluation method for future real-time assessment of clinical orthodontic forces.

Aircraft Observations of Liquid and Ice in Midlatitude Mixed-Phase Clouds

ABSTRACT This paper reports airborne measurements of midlatitude altostratus clouds observed over Zhengzhou, Henan Province, China on 3 March 2007. The case demonstrates mixed-phase conditions at altitudes from 3200 to 4600 m （0°C to -7.6°C）, with liquid water content ranging from 0.01 to 0.09 g m-3. In the observed mixed-phase cloud, liquid water content exhibited a bimodal distribution, whereas the maximum ice particle concentration was located in the middle part of the cloud. The liquid and ice particle data showed significant horizontal variability on the scale of a few hundred meters. The cloud droplet concentration varied greatly over the horizontal sampling area. There was an inverse relationship between the cloud droplet concentration and ice particle concentration. A gamma distribution provided the best description of the cloud droplet spectra. The liquid droplet distributions were found to increase in both size and concentration with altitude. It was inferred from the profile of the spectra parameters that the cloud droplet sizes tend to form a quasi-monodisperse distribution. Ice particle spectra in the cloud were fitted well by an exponential distribution. Finally, a remarkable power law relationship was found between the slope （λ） and intercept （No） parameters of the exponential size distribution.

The chaotification of discrete Hopfield neural networks via impulsive control

The chaotification of discrete Hopfield neural networks is studied with impulsive control techniques. No matter whether the original systems are stable or not, chaotilication theorems for discrete Hopfield neural networks are derived, respectively. Finally, the effectiveness of the theoretical results is illustrated by some numerical examples.

Information Feedback Strategies in a Signal Controlled Network with Overlapped Routes

We investigate the effects of four different information feedback strategies on the dynamics of traffic, travelers＇ route choice and the resultant system performance in a signal controlled network with overlapped routes. Simulation results given by the cellular automaton model show that the system purpose-based mean velocity feedback strategy and the congestion coefficient feedback strategy have more advantages in improving network utilization efficiency and reducing travelers＇ travel times. The travel time feedback strategy and the individual purposed-based mean velocity feedback strategy behave slightly better to ensure user equity.

Chaos Control and Synchronization of Cellular Neural Network with Delays Based on OPNCL Control

The problem of chaos control and complete synchronization of cellular neural network with delays is studied. Based on the open plus nonlinear closed loop （OPNCL） method, the control scheme and synchronization scheme are designed. Both the schemes can achieve the chaos control and complete synchronization of chaotic neural network respectively, and their validity is further verified by numerical simulation experiments.

Space Geodesy Application for the Natural Hazards Monitoring of the Russian Far Eastern Territory

This is a brief overview of the surveys aimed at the studies of the Russian Eastern Asian area, which has a complicate geological structure and tectonics, because of convergence of three tectonic plates （Eurasian--EUR, North American--NAM and Pacific--PAC）. An existenee of several independent microplates （Okhotsk--OKH, Amur--AMU and Bering--BER） is assumed to be there. A multinational Circum-Pacific geodetic network for monitoring the tectonic movements in the region is critical. From this point of view, new developed Russian fundamental geodetic network will be very effective.

Extracting inter-area oscillation modes using local measurements and data-driven stochastic subspace technique

In this paper, a data-driven stochastic subspace identification(SSI-DATA) technique is proposed as an advanced stochastic system identification(SSI) to extract the inter-area oscillation modes of a power system from wide-area measurements. For accurate and robust extraction of the modes’ parameters(frequency, damping and mode shape), SSI has already been verified as an effective identification algorithm for output-only modal analysis.The new feature of the proposed SSI-DATA applied to inter-area oscillation modal identification lies in its ability to select the eigenvalue automatically. The effectiveness of the proposed scheme has been fully studied and verified,first using transient stability data generated from the IEEE16-generator 5-area test system, and then using recorded data from an actual event using a Chinese wide-area measurement system(WAMS) in 2004. The results from the simulated and recorded measurements have validated the reliability and applicability of the SSI-DATA technique in power system low frequency oscillation analysis.

STABILITY OF LINEAR MEASURE LARGE SCALE SYSTEMS WITH IMPULSIVE EFFECT

Many impulsive phenomena from physics, control theory, and economics urge us toinvestigate measure large scale systems. In this paper, the variation of parameters formulaof the large scale systems containing measures is established. By means of inequality methods and comparison theory, the stability, uniform stability, asymptotic stability, uniformasymptotic stability, and exponential stability properties of linear measure large scale systems are studied.

Smart inverter operation in distribution networks with high penetration of photovoltaic systems

With the growing number and capacity of photovoltaic(PV)installations connected to distribution networks,power quality issues related to voltage regulation are becoming relevant problems for power distribution companies and for PV owners.In many countries,like Italy,this has required the revision of the standards concerning the connection to the public distribution network of distributed renewable generation.The new standards require a flexible operation of generation plants that have to be capable to change the active and reactive power dynamically in function of the network parameters(i.e.frequency and network local voltage)in local control or following external commands.Therefore,this paper investigates the use of smart inverter in a critical PV installation,where relevant voltage fluctuations exist.A case study,with real network parameters monitoring data and measurements,is discussed in the paper with the aim of showing how‘smart’features of new inverters can be implemented to increase PV plant integration in low voltage distribution networks.

A Survey of Repetitive Control for Nonlinear Systems

In aerospace engineering and industry, control tasks are often of a periodic nature,while repetitive control is especially suitable for tracking and rejection of periodic exogenous signals.Because of limited research effort on nonlinear systems, we give a survey of repetitive control for nonlinear systems in this paper.First,a brief introduction of repetitive control is presented.Then,after giving a brief overview of repetitive control for linear systems,this paper summarizes design methods and existing problems of repetitive control for nonlinear systems in detail.Lastly,relationships between repetitive control and other control schemes are analyzed to recognize repetitive control from different aspects more insightfully.

Robust Stabilization Control for a Class of Nonlinear Measure Differential Systems with Delay

This paper considers the robust stabilization problem of a class of nonlinear measure differential systems with delay.To eliminate the effect of nonlinear uncertainties on the stability of a closed loop system, a nonlinear controller is employed.In addition, to get the stability result of closed loop dynamics, two novel lemmas are proposed.In our approach, we do not require the assumption that the time varying delay variable γ(t) be restricted by (t)【1 , which is often required in many previous papers (e.g,see).

Observer-Based Robust Control for Measure Differential Systems with Parameter Uncertainty and Time Delay

In this paper, we propose a robust control based on the observer for a class of measure differential systems with time delay. To implement the control, we only need the output signal of the systems. In the finial section, a numerical example is given to illustrate the effectiveness of the proposed scheme.

Global Exponential Stability of Variable Delay and Time－varying Measure Differential Systems with Impulse Effect

This work concerns the stability properties of impulsive solution for a class of variable delay and time-varying measure differential systems. By means of the techniques of constructing broken line function to overcome the difficulties in employing comparison principle and Lyapunov function with discontinuous derivative, some criteria of global exponential asymptotic stability for the system are established. An example is given to illustrate the applicability of results obtained.