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VO HOANG DUY,NGUYEN HUNG,SANG-KWUN JEONG,HAK-KYEONG KIM,SANG-BONG KIM 한국해양공학회 2008 韓國海洋工學會誌 Vol.22 No.4
This paper proposes a mixed H₂/H∞ optimal PID controller with a genetic algorithm based on the dynamic model of a brushless direct current (BLDC) motor and applies it to speed control. In the dynamic model of the BLDC motor with perturbation, the proposed controller guarantees arobust and optimal tracking performance to the desired speed of the BLDC motor. A genetic algorithm was used to obtain parameters for the PID controller that satisfy the mixed H2/H∞ constraint. To implement the proposed controller, a control system based on PIC18F4431 was developed. Numerical and experimental results are shown to prove that the performance of the proposed controller was better than that of the optimal PID controller.
Vo Hoang Duy,Nguyen Thanh Phuong,김학경(Hak Kyeong Kim),김상봉(Sang Bong Kim) 한국마린엔지니어링학회 2006 한국마린엔지니어링학회 학술대회 논문집 Vol.2006 No.-
A mixed method between H₂ and H<SUB>∞</SUB> control are widely applied to systems which has parameter perturbation and uncertain model to obtain an optimal robust controller. Brushless Direct Current (BLDC) motors are widely used for high performance control applications. Conventional PID controller only provides satisfactory performance for set-point regulation. However, with the presence of nonlinearities, uncertainties and perturbations in the system, conventional PID is not sufficient to achieve an optimal robust controller. This paper presents an approach to ease designing a Mixed H₂/H<SUB>∞</SUB> PID controller for controlling speed of Brushless DC motors and the genetic algorithm is used to solve the optimized problems. Numerical results are shown to prove that the performance in the proposed controller is better than that in the optimal PID controller using LQR approach.
Structural defects and thermodynamics of vitreous GeO_2 nanoparticles
Vo Van Hoang,Tran Phuoc Duy 한국물리학회 2011 Current Applied Physics Vol.11 No.3
Structural defects and thermodynamics of vitreous GeO_2 nanoparticles have been studied in spherical models of different sizes ranged from 2 to 5 nm. Models have been obtained by cooling from the melts via using molecular dynamics (MD) method with the ab initio pair interatomic potentials. Structural properties were investigated via partial radial distribution function (PRDF), interatomic distances, bondangle and coordination number distributions. Surface and core structure of amorphous GeO_2 nanoparticles have been studied in details. Structural defects and their role in structure and properties of nanoparticles have been analyzed and discussed. We found temperature (and size) dependence of potential energy, surface energy of GeO_2 nanoparticles. We also found the size dependence of glass transition temperature of nanoparticles.
Ngo Manh Dung,Vo Hoang Duy,Nguyen Thanh Phuong,Sang Bong Kim,Myung Suck Oh 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.3
In this paper, a nonlinear controller based on adaptive sliding-mode method which has a sliding surface vector including new boundizing function is proposed and applied to a two-wheeled welding mobile robot (WMR). This controller makes the welding point of WMR achieve tracking a reference point which is moving on a smooth curved welding path with a desired constant velocity. The mobile robot is considered in view of a kinematic model and a dynamic model in Cartesian coordinates. The proposed controller can overcome uncertainties and external disturbances by adaptive sliding-mode technique. To design the controller, the tracking error vector is defined, and then the sliding surface vector including new boundizing function and the adaptation laws are chosen to guarantee that the error vector converges to zero asymptotically. The stability of the dynamic system is shown through the Lyapunov method. In addition, a simple way of measuring the enol'S by potentiometers is introduced. The simulations and experimental results are shown to prove the effectiveness of the proposed controller.
A New Approach for Development of Quadruped Robot Based on Biological Concepts
Phuc Thinh Doan,Hoang Duy Vo,김학경,김상봉 한국정밀공학회 2010 International Journal of Precision Engineering and Vol.11 No.4
This paper proposes the design and development results of a new quadruped robot. The proposed new quadruped robot has a couple of advantages of flexible locomotion. The quadruped robot is designed and modeled based on a new concept that is the structure model with three segments of quadruped legs. New leg configuration with the simplified operation of four hip actuators is introduced. The posture of the new quadruped robot is more similar to the posture of dog than that of the previous quadruped robots. The objective of this paper is to develop a quadruped robot, which can walk and run in a trot gait with a simple PID controller. Numerical simulation and experimental results are shown to prove the locomotion performance of the proposed controller for the proposed quadruped robot.
Thuy Thi Le Bui,Ha Thi Ngoc Uong,Duy Khac Nguyen,Dung Thi Kim Hoang,Giang Vo-Thanh 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.12
Platinum(IV) was extracted from chloride solution using kerosene solution of trioctyl ammonium chloride, methyltrioctylammonium chloride, and tetraoctyl ammonium chloride ionic liquids as solvents in high yields. To increase the Pt(IV) recovery and heterogenize the process for easy handling at industrial scale, these three ionic liquids were directly impregnated on some solid carriers, such as silica gel-60, silica gel-100, Amberlite XAD-7 ion-exchange resin, and Amberlite XAD-7 ion-exchange resin to form sorbents in nature of supported ionic liquid phase. The influence of some factors, such as ionic liquid and solid carrier structure, IL/Pt molar ratio, and ionic liquid loading as well as sorption isotherms, was investigated. The stripping and desorption of Pt(IV) using different eluents and reusability of ionic liquids and supported ionic liquid phases were also evaluated.
Line Impedance Estimation Based Adaptive Droop Control Method for Parallel Inverters
Phuong Minh Le,Xuan Hoa Thi Pham,Huy Minh Nguyen,Duc Duy Vo Hoang,Tuyen Dinh Nguyen,Dieu Ngoc Vo 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1
This paper presents a new load sharing control for use between paralleled three-phase inverters in an islanded microgrid based on the online line impedance estimation by the use of a Kalman filter. In this study, the mismatch of power sharing when the line impedance changes due to temperature, frequency, significant differences in line parameters and the requirements of the Plug-and-Play mode for inverters connected to a microgrid has been solved. In addition, this paper also presents a new droop control method working with the line impedance that is different from the traditional droop algorithm when the line impedance is assumed to be pure resistance or pure inductance. In this paper, the line impedance estimation for parallel inverters uses the minimum square method combined with a Kalman filter. In addition, the secondary control loops are designed to restore the voltage amplitude and frequency of a microgrid by using a combined nominal value SOGI-PLL with a generalized integral block and phase lock loop to monitor the exact voltage magnitude and frequency phase at the PCC. A control model has been simulated in Matlab/Simulink with three voltage source inverters connected in parallel for different ratios of power sharing. The simulation results demonstrate the accuracy of the proposed control method.
Tien Manh Huynh,Khanh Quoc Le Tran,Trung Hoang Dinh,Man Minh Vo,Thong Quang Pham,Thong Duy Vo 대한소화기학회 2024 대한소화기학회지 Vol.83 No.6
Toxocariasis, a zoonotic infection transmitted by Toxocara canis (from dogs) and Toxocara cati (from cats) larvae, poses rare but severe risks to humans. We present a case of hepatic visceral larva migrans (VLM) caused by Toxocara canis in a 21-year-old male with a history of close contact with a pet dog. Initial symptoms and imaging findings mimicked a pyogenic liver abscess. The initial laboratory investigations revealed neutrophilia and elevated levels of IgE. Despite broad-spectrum antibiotics, persistent fever prompted further investigation. Subsequent serological testing for Toxocara antibodies and histopathological analysis of liver tissue demonstrating eosinophil infiltrates and Charcot-Leyden crystals led to a confirmed diagnosis of a liver abscess caused by Toxocara canis. Serological testing for Toxocara antibodies and histopathological analysis of liver tissue confirmed a Toxocara canis-induced liver abscess. Albendazole treatment yielded significant clinical improvement. This case highlights the necessity of considering toxocariasis in liver abscess differentials, particularly in high-seroprevalence regions like Vietnam. Relying solely on serological tests may be insufficient, emphasizing the need for corroborative evidence, including invasive procedures like liver biopsy, for accurate hepatic toxocariasis diagnosis.
Line Impedance Estimation Based Adaptive Droop Control Method for Parallel Inverters
Le, Phuong Minh,Pham, Xuan Hoa Thi,Nguyen, Huy Minh,Hoang, Duc Duy Vo,Nguyen, Tuyen Dinh,Vo, Dieu Ngoc The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1
This paper presents a new load sharing control for use between paralleled three-phase inverters in an islanded microgrid based on the online line impedance estimation by the use of a Kalman filter. In this study, the mismatch of power sharing when the line impedance changes due to temperature, frequency, significant differences in line parameters and the requirements of the Plug-and-Play mode for inverters connected to a microgrid has been solved. In addition, this paper also presents a new droop control method working with the line impedance that is different from the traditional droop algorithm when the line impedance is assumed to be pure resistance or pure inductance. In this paper, the line impedance estimation for parallel inverters uses the minimum square method combined with a Kalman filter. In addition, the secondary control loops are designed to restore the voltage amplitude and frequency of a microgrid by using a combined nominal value SOGI-PLL with a generalized integral block and phase lock loop to monitor the exact voltage magnitude and frequency phase at the PCC. A control model has been simulated in Matlab/Simulink with three voltage source inverters connected in parallel for different ratios of power sharing. The simulation results demonstrate the accuracy of the proposed control method.