A Revisit to the Design of Switched Observers for Switched Linear Systems with Unknown Inputs

Gan-Ji Huang,Wu-Hua Chen 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.5

This paper revisits the problem of designing switched observers for switched linear systems with unknown inputs. By performing a state and output coordinates transformation that decouples the unknown input, a novel piecewise time-varying Lyapunov function is introduced to analyze the stabil-ity of the switched error dynamics. Compared with the existing time-invariant Lyapunov function method, the proposed time-varying Lyapunov function method is more suitable to exploit the structural characteristics of switched linear systems. New conditions are derived that guarantee the exponential stability of the switched error dynamics. These conditions are formulated in term of linear matrix inequalities (LMIs). By solving a set of LMIs, the switched observers can be designed. Two numerical examples are provided to illustrate the effectiveness of the proposed method.

A dynamic finite element method for the estimation of cable tension

Huang, Yonghui,Gan, Quan,Huang, Shiping,Wang, Ronghui 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.68 No.4

Cable supported structures have been widely used in civil engineering. Cable tension estimation has great importance in cable supported structures' analysis, ranging from design to construction and from inspection to maintenance. Even though the Bernoulli-Euler beam element is commonly used in the traditional finite element method for calculation of frequency and cable tension estimation, many elements must be meshed to achieve accurate results, leading to expensive computation. To improve the accuracy and efficiency, a dynamic finite element method for estimation of cable tension is proposed. In this method, following the dynamic stiffness matrix method, frequency-dependent shape functions are adopted to derive the stiffness and mass matrices of an exact beam element that can be used for natural frequency calculation and cable tension estimation. An iterative algorithm is used for the exact beam element to determine both the exact natural frequencies and the cable tension. Illustrative examples show that, compared with the cable tension estimation method using the conventional beam element, the proposed method has a distinct advantage regarding the accuracy and the computational time.

A dynamic finite element method for the estimation of cable tension

Yonghui Huang,Quan Gan,Shiping Huang,Ronghui Wang 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.68 No.4

Cable supported structures have been widely used in civil engineering. Cable tension estimation has great importance in cable supported structures’ analysis, ranging from design to construction and from inspection to maintenance. Even though the Bernoulli-Euler beam element is commonly used in the traditional finite element method for calculation of frequency and cable tension estimation, many elements must be meshed to achieve accurate results, leading to expensive computation. To improve the accuracy and efficiency, a dynamic finite element method for estimation of cable tension is proposed. In this method, following the dynamic stiffness matrix method, frequency-dependent shape functions are adopted to derive the stiffness and mass matrices of an exact beam element that can be used for natural frequency calculation and cable tension estimation. An iterative algorithm is used for the exact beam element to determine both the exact natural frequencies and the cable tension. Illustrative examples show that, compared with the cable tension estimation method using the conventional beam element, the proposed method has a distinct advantage regarding the accuracy and the computational time.

Structural Phase Formation and Tunable Luminescence of Eu2+-Activated Apatite-Type (Ca,Sr,Ba)5(PO4)2(SiO4)

Huang, Yanlin,Gan, Jiuhui,Zhu, Rui,Wang, Xigang,Seo, Hyo Jin The Electrochemical Society 2011 Journal of the Electrochemical Society Vol.158 No.11

Luminescence Investigation of Eu-Activated Sr5(PO4)2SiO4 Phosphor by Combustion Synthesis

Huang, Y.,Gan, J.,Seo, H. J. Blackwell Publishing Ltd. 2011 Journal of the American Ceramic Society Vol.94 No.4

Development of devices and methods for simulation of hurricane winds in a full-scale testing facility

Huang, Peng,Chowdhury, Arindam Gan,Bitsuamlak, Girma,Liu, Roy Techno-Press 2009 Wind and Structures, An International Journal (WAS Vol.12 No.2

The International Hurricane Research Center (IHRC) at Florida International University (FIU) is pursuing research to better understand hurricane-induced effects on residential buildings and other structures through full-scale aerodynamic and destructive testing. The full-scale 6-fan Wall of Wind (WoW) testing apparatus, measuring 4.9 m tall by 7.3 m wide, is capable of generating hurricane-force winds. To achieve windstorm simulation capabilities it is necessary to reproduce mean and turbulence characteristics of hurricane wind flows. Without devices and methods developed to achieve target wind flows, the full-scale WoW simulations were found to be unsatisfactory. To develop such devices and methods efficiently, a small-scale (1:8) model of the WoW was built, for which simulation devices were easier and faster to install and change, and running costs were greatly reduced. The application of such devices, and the use of quasiperiodic fluctuating waveforms to run the WoW fan engines, were found to greatly influence and improve the turbulence characteristics of the 1:8 scale WoW flow. Reasonable reproductions of wind flows with specified characteristics were then achieved by applying to the full-scale WoW the devices and methods found to be effective for the 1:8 scale WoW model.

Anatomical Adaptations of the Xerophilous Medicinal Plant, Capparis spinosa, to Drought Conditions

Lu Gan,Chunyu Zhang,Yongtai Yin,Zhiwei Lin,Yongwei Huang,Jun Xiang,Chunhua Fu,Maoteng Li 한국원예학회 2013 Horticulture, Environment, and Biotechnology Vol.54 No.2

Capparis spinosa is a plant that grows in dry and arid environments. As far as can be ascertained, no comprehensive studies on how the leaf, stem and root structures adapt to drought conditions have been published to date. In this paper, a study into the anatomical adaptations of the leaf, stem and root of C. spinosa to drought environments was conducted using in vitro cultured seedlings as control. The results showed that C. spinosa could change its leaf, stem, and root structures when adapting to drought conditions. The plant growing under drought conditions possessed an enlarged transit region between the stem and root where the xylem and fibro-vascular system had increased in order to enhance water absorption and storage capacity. The leaf, stem and root of C. spinosa under drought conditions were better developed than those under normal in vitro culture conditions. The leaf possessed uniform mesophyll cells and three or four layers of palisade mesophyll cells on both sides of the mature leaves. The stomata were evenly distributed across both sides of the leaf, and they remained open continually during the day throughout the summer growing period, especially those on the lower leaf surface. The xylem in the stem was extremely well developed with wide vessels and much thicker cortical layers. All these characteristics can enhance the adaptability of C. spinosa and enable it to survive in extremely dry and arid areas.

INFLUENCE OF HEAT TRANSFER OF COMBUSTION CHAMBER WALL ON THE PERFORMANCE OF GASOLINE ENGINE BASED ON POLISHING TECHNOLOGY UNDER DIFFERENT COMPRESSION RATIO AND AIR-FUEL RATIO

Zhaoming Huang,Zijun Zheng,Tao Wang,Li Wang,Hongcheng Gan,Weiguo Chen 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4

On a single-cylinder gasoline engine test bench, the experimental study of the effects of polishing the combustion chamber wall and piston top surface on the indicated thermal efficiency and combustion characteristics were carried out, and the mutual influence of combustion phase, combustion duration and indicated thermal efficiency before and after polishing the wall of combustion system was systematically analyzed. The results show that when the single-cylinder gasoline engine operates at stoichiometric air-fuel ratio, low load and low compression ratio, the heat transfer loss of the polished combustion chamber is reduced and the fuel economy is improved, and the indicated thermal efficiency is increased from 40.8 to 42.2 %. With the increasing of load and compression ratio, the knock effect caused by the reduction of heat transfer loss after polishing is enhanced, and the combustion phase is delayed and the combustion duration is prolonged, which eventually leads to the decrease of the indicated thermal efficiency. After combustion chamber polishing, HC and NOx decrease by up to 70 %. With the increase of compression ratio, HC emission gradually increases, while NOx emission gradually decreases. There is no obvious change trend of CO emission before and after polishing. When the gasoline engine operates in lean combustion mode, the indicated thermal efficiency increases effectively, and the highest thermal efficiency exceeds 45 %; When the gasoline engine operates at indicated mean effective pressure of 1.05 MPa, the reduction of heat transfer loss in the combustion chamber after polishing enhances the knocking tendency, resulting in the overall decrease of the gross indicated thermal efficiency compared with that before polishing.

Development of devices and methods for simulation of hurricane winds in a full-scale testing facility

Peng Huang,Arindam Gan Chowdhury,Girma Bitsuamlak,Roy Liu 한국풍공학회 2009 Wind and Structures, An International Journal (WAS Vol.12 No.2

The International Hurricane Research Center (IHRC) at Florida International University (FIU) is pursuing research to better understand hurricane-induced effects on residential buildings and other structures through full-scale aerodynamic and destructive testing. The full-scale 6-fan Wall of Wind (WoW) testing apparatus, measuring 4.9 m tall by 7.3 m wide, is capable of generating hurricane-force winds. To achieve windstorm simulation capabilities it is necessary to reproduce mean and turbulence characteristics of hurricane wind flows. Without devices and methods developed to achieve target wind flows, the full-scale WoW simulations were found to be unsatisfactory. To develop such devices and methods efficiently, a small-scale (1:8) model of the WoW was built, for which simulation devices were easier and faster to install and change, and running costs were greatly reduced. The application of such devices, and the use of quasiperiodic fluctuating waveforms to run the WoW fan engines, were found to greatly influence and improve the turbulence characteristics of the 1:8 scale WoW flow. Reasonable reproductions of wind flows with specified characteristics were then achieved by applying to the full-scale WoW the devices and methods found to be effective for the 1:8 scale WoW model.

Energy Consumption Evaluation in Stamping Workshops via a Discrete Event Simulation-Based Approach

Wei Xiong,Haihong Huang,Lei Li,Lei Gan,Libin Zhu,Zhifeng Liu 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.6

Stamping is employed in a wide range of applications in industry, which is composed of discrete flow energy-intensive processes. Durations of stamping activities are much shorter than that of mold changing and transportation, which makes energy consumption in stamping workshops greatly affected by the production scheme and the proportion of transportation volume. Different from machining that has been widely discussed, there is less research on energy saving in stamping workshops. This paper aims to evaluate the energy consumption of stamping on the workshop level. A theoretical model and a discrete event simulation model were developed based on energy flow and material flow in the workshop. The theoretical model was used to calculate each component of energy consumption based on production-related data. The simulation model was used to predict the overall energy required in the workshop when subjected to changes in its production conditions. Impacts of influence factors, including machine failure rate, proportion of transportation volume, and production scheme on energy consumption, makespan, and machine utilization rates, were studied to find opportunities for energy reduction and production efficiency improvement. Finally, a case study of a stamping workshop for forklifts validated the proposed approach, and optimization measures were suggested, implemented, and verified. Results have found that under the same production scheme (suppose each press has the same failure rate), the balance between energy use and makespan was achieved when the proportion of transportation volume was 1/2. This simulation-based approach provides a useful tool for evaluating and reducing energy consumption and helps operators to perform energy-saving actions in stamping workshops.