Fault Estimation and Accommodation for Switched Systems with Time-varying Delay

Dongsheng Du,Bin Jiang,Peng Shi 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.3

This paper considers the problem of fault estimation and accommodation for a class of switched systems with time-varying delay. An adaptive fault estimation algorithm is proposed to estimate the fault, moreover, constant or time-varying fault can be estimated. Meanwhile, a delay-dependent criteria is obtained with the purpose of reducing the conservatism of the fault estimation algorithm design. On the basis of fault estimation, an observer-based fault tolerant controller is designed to guarantee the stability of the closed-loop system. Additionally, simulation results are presented to il-lustrate the efficiency of the proposed results.

Robust Fault Diagnosis Observer Design for Uncertain Switched Systems

Dongsheng Du,Yue Yang,Huanyu Zhao,Yushun Tan 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.12

In order to improve the fault diagnosis theory of switched systems, observer-based method is proposed to deal with the fault diagnosis issue subjected to the parameter uncertainty, unknown process disturbances and unexpected faults. By employing proportional-integral observer (PIO) technique and the average dwell-time (ADT) method, an H∞/H− performance level is considered to ensure the worst case of robustness to the disturbance and sensitivity to the fault simultaneously. Moreover, the obtained fault diagnosis observer can give accurate fault estimation online for the piecewise constant fault. Finally, a two-tank system example is introduced in the end to show the effectiveness of the proposed results.

Actuator Fault Detection for Discrete-time Switched Linear Systems with Output Disturbance

Dongsheng Du,Shengyuan Xu 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.6

In this paper, the problem of actuator fault detection for discrete-time switched systems with outputdisturbance is investigated. By using the descriptor observer method, an H∞ fault detection filter is designed toguarantee that the augmented system is admissible and satisfies a prescribed H∞ performance index. By utilizingswitched Lyapunov function approach, a sufficient condition for the admissible of the augmented system is obtained. Based on the obtained results, a desired fault detection filter can be designed. All the results are formulated in theform of linear matrix inequalities. Finally, an example is proposed to illustrate the effectiveness of the developedmethod.

Global anaysis of B → PP, PV charmless decays with QCD factorization

Dongsheng Du 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.2

The global analysis of B ! PP, PV charmless decays with QCD factorization (QCDF) is presented. The predictions of QCDF are in good agreement with experiments. The best tted CKM angle is around 79. The predicted branching ratios of B ! 00, !K+, !+, +K0 etc. are also in good agreement with new data of BaBar and Belle.

Non-destructive evaluation and pattern recognition for SCRC columns using the AE technique

Du, Fangzhu,Li, Dongsheng Techno-Press 2019 Structural monitoring and maintenance Vol.6 No.3

Steel-confined reinforced concrete (SCRC) columns feature highly complex and invisible mechanisms that make damage evaluation and pattern recognition difficult. In the present article, the prevailing acoustic emission (AE) technique was applied to monitor and evaluate the damage process of steel-confined RC columns in a quasi-static test. AE energy-based indicators, such as index of damage and relax ratio, were proposed to trace the damage progress and quantitatively evaluate the damage state. The fuzzy C-means algorithm successfully discriminated the AE data of different patterns, validity analysis guaranteed cluster accuracy, and principal component analysis simplified the datasets. A detailed statistical investigation on typical AE features was conducted to relate the clustered AE signals to micro mechanisms and the observed damage patterns, and differences between steel-confined and unconfined RC columns were compared and illustrated.

Cluster analysis and damage identification for FRP/steel-confined RC column using AE technique

Fangzhu Du,Dongsheng Li,Dapeng Qiu 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.27 No.3

This article presents the damage evaluation and pattern recognition for the newly proposed fiber reinforced polymer (FRP)/steel-confined reinforced concrete columns. The interaction of FRP material, steel tube, and reinforced concrete lead to complex damage mechanisms and invisible damage modes. The prevailing acoustic emission (AE) technique was applied to monitor the damage process and detect the sheltered damages under cyclic loading. Characteristic AE parameters, such as energy and duration, were extracted to disclose the damage evolution and evaluate the damage state. Three typical damage stages were identified. The fuzzy C.means (FCM) algorithm and particle swarm optimization (PSO) algorithm were applied as efficient clustering tools to discriminate different damage signals of FRP/steel-confined RC columns. Five types of damage mechanisms were identified and illustrated based on the statistical analysis of typical AE features. Furthermore, typical damage waveforms were extracted, the frequency content of each damage signal was discussed on the basis of wavelet transform.

The vertical distribution and temporal occurrence of three types of rice planthoppers in Shanghai

Wang Dongsheng,Wu Xiangwen,Yuan Yongda,Zhang Tianshu,Shen Huimei,Du Xingbin,Teng Haiyuan,Chang Xiaoli 한국곤충학회 2022 Entomological Research Vol.52 No.1

In this study, we investigated the dynamic occurrence and vertical distribution of three types of rice planthoppers (Nilaparvata lugens, Sogatella furcifera,and Laodelphax striatellus) in Shanghai, China. Our results showed that S. furcifera and L. striatellus infested the lower part of rice plants in the early development stage, S. furcifera and L. striatellus inhabited every part of rice in the middle development stage, and L. striatellus and N. lugens formicated in the upper part of the rice plant in the posterior development stage. The populations of rice planthoppers were larger in July and September, Where more than 600 adult and nymphal planthoppers, per a hundred hills of rice, were found in late July, and out of the 600, the majority were the nymphs of S. furcifera and L. striatellus. S. furcifera was mainly found from July to October, L. striatellus during the rice development, and N. lugens after September, during which their maximal individual number, per a hundred hills of rice, was 480, 220, less than 50, respectively. In addition, our results showed that adult rice planthoppers were mostly observed from late August to mid-October with the highest population being found during mid to late September. The adult S. furcifera, L. striatellus,andN. lugens were mostly observed in August and September, from August to October, and past mid-September, respectively. Moreover, the number of adult L. striatellus that were sticking to yellow sticky card was significantly higher than that of S. furcifera and N. lugens.

UIO-based Fault Estimation and Accommodation for Nonlinear Switched Systems

Haoshuang Chen,Dongsheng Du,Dewen Zhu,Yan Yang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.2

This paper investigates the problems of fault estimation and fault accommodation for a class of nonlinearswitched systems. First, an augmented switched system is constructed by forming an augmented state vectorcomposed of the state vector and the fault vectors. Then, an unknown input observer (UIO) is designed for theaugmented switched system to estimate the augmented state vector. With the assist of the average dwell-time(ADT) method and the switched Lyapunov function technique, sufficient conditions are obtained to guarantee thatthe error system is globally uniformly asymptotically stable (GUAS) with a prescribed H∞ performance index. Analgorithm is provided to show the procedures on how to design the UIO. Moreover, the results are extended to themeasurement disturbances case. Based on signal compensation principle, a dynamic output feedback controller isdesigned to ensure the asymptotical stability of the closed-loop system. Finally, simulation results are presented todemonstrate the proposed technique.

Effects of Different Blade Numbers on Radial Exciting Force of Lobe Pump Rotor

Yibin Li,Dongsheng Guo,Zhaojing Fan,Jun Du 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.2

In order to clarify the relationship between different blade numbers and radial exciting force of the rotary lobe pump rotor, five rotary lobe pumps with different blade numbers were researched based on the dynamic mesh techniques using RNG k-ε turbulence model and PISO algorithm. The internal flow characteristics in the pump are compared and the influence mechanism of the different blade numbers on the transient flow structure and the exciting force inside the rotor cavity are revealed. Meanwhile, through numerical simulation and experimental verification, the comparative analysis of numerical prediction shows that the relative error is less than 5.6%, and the numerical simulation has higher accuracy. The results show that the number of blade has a significant effect on the flow characteristics and radial exciting force distribution of rotor cavity of the rotary lobe pump. With the increase of the number of blades, the average flow rate and the flow pulsation amplitude of the flow rate at the outlet of the pump are obviously decreased, which effectively inhibits the secondary flow, vortex and the velocity abrupt change between the rotor gaps region of the rotor cavity. The maximum radial exciting force at 6 blade numbers is less 36% than that at 4 blade numbers. A multistage series transition cavity is formed between the high-pressure cavity and the low-pressure cavity when the blades number of 5 and 6 which can effectively reduce the pressure difference between the two sides of the radial gaps. It can reduce the radial leakage, and effectively suppress the instantaneous pressure relief effect caused by the instantaneous opening of the gaps.

Fault Detection for Discrete-time Switched Systems with Interval Time-varying Delays

Bin Jiang,Dongsheng Du,Vincent Cocquempot 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.2

This paper investigates the problem of fault detection filter design for discrete-time switched systems with interval time-varying delays. The residual generator is constructed based on a mode-dependent fault detection filter, i.e., the designed fault detection filter is also a switched system as well. By constructing a novel switched Lyapunov functional, a new criterion is obtained for the residual system. Based on this, a sufficient condition for the existence of the above filter is established in terms of linear matrix inequalities (LMIs). The designed fault detection filter can guarantee the difference between the generated residual signal and the fault signal as small as possible. An example is provided to illustrate the effectiveness of the proposed method.