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Vu Dinh Quang,Nguyen Dinh Khoa,Nguyen Dinh Duc 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8
This research examines the influent of structural characteristics (shape, size, material properties, porosity), external conditions (mechanical load, thermal load, and foundation parameters) on the vibration and nonlinear dynamic response of shear deformable porous plates made of functionally graded materials (FGM) in the thermal environment and rested on the Pasternak’s elastic foundation. Reddy’s third-order shear deformation theory (TSDT) and von Kármán’s geometric nonlinearity are used to explore the structural behavior of thick FGM porous plates with two types of porosity distribution in FGM porous plates namely, even and uneven patterns. The solutions are obtained through the Bubnov-Galerkin method and RungeKutta methods. The outcomes are compared with other research in the result section to assess the reliability of the solution method in the paper.
Do Quang Chan,Pham Dinh Nguyen,Vu Dinh Quang,Vu Thi Thuy Anh,Nguyen Dinh Duc 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.31 No.3
This study deals with the nonlinear static analysis of functionally graded carbon nanotubes reinforced composite (FG-CNTRC) truncated conical shells subjected to axial load based on the classical shell theory. Detailed studies for both nonlinear buckling and post-buckling behavior of truncated conical shells. The truncated conical shells are reinforced by single-walled carbon nanotubes which alter according to linear functions of the shell thickness. The nonlinear equations are solved by both the Airy stress function and Galerkin method based on the classical shell theory. In numerical results, the influences of various types of distribution and volume fractions of carbon nanotubes, geometrical parameters, elastic foundations on the nonlinear buckling and post-buckling behavior of FG-CNTRC truncated conical shells are presented. The proposed results are validated by comparing with other authors.
Dinh Quang Truong,Ahn Kyoung Kwan,Jong Il Yoon 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
Nowadays, hydraulic actuators play an important role in a modern industry where controlled force or position with high accuracy is the most significant demand. This paper presents a new kind of electric-hydraulic load simulator (HLS) for conducting performance and stability test in the bench system where force control is important. The system model consists of a hybrid hydro-electric actuator and another hydraulic circuit generating disturbances. For the purpose of improving force control performance of hydraulic hybrid systems, an online tuning force controller based Quantitative Feedback Theory (QFT) technique is applied to the load simulator and also proposed in this paper. The controller is firstly designed to satisfy the robust performance requirement, tracking performance specification, and disturbance attenuation despite uncertainties of the load simulator system. Secondly, by using gradient descent method it becomes an online tuning QFT controller during the system operation process to adapt with a wide range of working conditions including perturbations. Experiments are carried out to evaluate the effectiveness of the proposed control method applied for the electric-hydraulic load simulator systems.
Robust Variable Sampling Period Control for Networked Control Systems
Dinh Quang Truong,Kyoung Kwan Ahn Institute of Electrical and Electronics Engineers 2015 IEEE transactions on industrial electronics Vol. No.
<P>The aim of this paper is to develop a novel robust variable sampling period controller (RVSPC) for networked control systems (NCSs) in the presence of random time delays and packet losses. Different from the existing control techniques for NCSs, the RVSPC controller is constructed as a hybrid robust controller with the adaptive variable sampling period. To adapt to the delay variation, a so-called variable sampling period adjuster based on a time delay predictor (TDP) and a time delay and packet detector is designed to adjust effectively the sampling period. To efficiently compensate for the random delays and packet losses, the hybrid controller is designed as a combination of a quantitative feedback theory (QFT)-based robust controller and a robust state feedback controller (RSFC) with adaptive control gain. A smart switch based on the TDP is then used to select properly the main control unit as the QFT or RSFC corresponding to the current delay and packet loss status. Illustrative examples with NCSs including both computation and communication delays and packet losses are finally carried out to illustrate the effectiveness of the proposed method.</P>
Dinh Quang Truong,Kyoung Kwan Ahn,Doan Ngoc Chi Nam,Jong Il Yoon 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
An ion polymer metal composite (IPMC) is an electro-active polymer that bends in response to a small applied electrical field as a result of mobility of cations in the polymer network and vice versa. This paper presents a novel accurate nonlinear black-box model (NBBM) for estimating the bending behavior of IPMC. The NBBM is based on a recurrent multi-layer perceptron neural network (RMLPNN) and a self-adjustable learning mechanism (SALM). The model parameters are optimized by using training data. A comparison of the estimated and real IPMC bending characteristic has been done to investigate the modeling ability of the designed NBBM.
Fuzzy Encoding Pattern for Stereo Matching Cost
Dinh, Vinh Quang,Nguyen, Vinh Dinh,Van Nguyen, Hau,Jeon, Jae Wook IEEE 2016 IEEE Transactions on Circuits and Systems for Vide Vol.26 No.7
<P>We propose a novel fuzzy encoding pattern that fuzzily encodes the relative orders between pixel pairs. An image window is divided into disjoint neighboring pixel sets for the window's center pixel, and the relative order is established not only between the center pixel and its neighbors but also between the pixel pairs in each neighboring pixel set. The relative orders are fuzzily encoded to extract more detailed information from a local structure. We successfully apply the pattern as a matching cost function for stereo correspondence under severe radiometric variations. We conduct experiments using the proposed matching cost function and compare it with functions employing the census transform, supporting local binary pattern, and adaptive normalized cross correlation, as well as a mutual information-based matching cost function, using different stereo data sets. Compared with the census transform, the proposed function reduces the error from 33.1% to 16.9% in the Middlebury data set and from 17.6% to 9.5% in the Kitti data set. The experimental results indicate that the proposed function is superior to the state-of-the-art functions under radiometric variations. In addition, the proposed function is faster than recently developed functions, such as the adaptive normalized cross correlation, a mutual information-based function, and support local binary pattern.</P>
Dinh Quang Truong,Kyoung Kwan Ahn,Jong Il Yoon 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
This paper presents an application of an electro-hydraulic actuator (EHA) and a novel control method ?online tuning modified-Grey fuzzy PID controller (OTMGFPID) to a steel rolling machine (SRM) in POSCO Corp. in order to improve its working performance. In this SRM, the center position of the roller, which affects directly the rolling quality, is controlled by the EHA system instead of using a conventional servo hydraulic actuator (SHA). To enhance the center position control (CPC) performance, the OTMGFPID which is a combination of a main control unit, online tuning fuzzy PID controller (OTFPID), and an online tuning modified-Grey predictor (OTMGP) is designed for the EHA. The OTMGP with self tuning ability of its predictor step size based on fuzzy technique (called FPSS) is used to estimate the actual system output and to create a compensating control signal corresponding to the system perturbations, consequently, improving the control quality. The ability of using the EHA and OTMGFPID controller for the SRM with CPC is verified by simulated force control target of a press machine using EHA. Simulation results prove that the EHA as well as the proposed controller has strong potential to be applied for CPC of the SRM.
Force-Sensorless Damping Control for Damping Systems using MR Dampers
Dinh Quang Truong,Kyoung Kwan Ahn 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10
Recently, magneto-rheological (MR) fluid dampers are semi-active control devices that have begun to receive more attention. This paper presents a novel force-sensorless control method for a damping system using a MR damper. The control method is constructed by two models designed based on fuzzy-neural technique, a nonlinear black-box model (BBM) and an inverse black-box model (IBBM). By employing a fuzzy mapping system optimized by neural network technique including back-propagation and gradient descent method, the BBM model can estimate directly the damper characteristics. The inverse model, IBBM with self-learning ability, was then derived based on the BBM with the optimized parameters and neural network technique. Consequently, the designed BBM and IBBM models can be used as a ‘virtual’ force sensor and an adaptive force controller, respectively, to perform a closed-loop feedback control for any damping system which uses the corresponding MR fluid damper. Effectiveness of the proposed models for modeling as well as the force-sensorless damping control technique has been clearly verified through simulations and real-time experiments on two vibrating systems employing the same MR fluid damper series.
Dinh Trong Quang,Keiji Goto,Toru Kawano,Toyohiko Ishihara 한국전자파학회JEES 2012 Journal of Electromagnetic Engineering and Science Vol.12 No.1
When the cylindrical wave is incident on a plane dielectric interface from a denser medium to a rarer one, the asymptotic solution for the transmitted wave in the near region is different from the one in the far region. In this paper, we have derived a novel uniform asymptotic solution represented by using the parabolic cylinder function for the transmitted and scattered waves observed in the rarer medium when the cylindrical wave is incident on the plane dielectric interface from the denser medium. The validity of the uniform asymptotic solution has been confirmed by comparing with the reference solution calculated numerically. It has been clarified that the transition wave plays an important role to connect smoothly the asymptotic solution in the near region to the one in the far region through the transition region. We have shown the very interesting phenomenon that the lateral wave type transmitted wave is observed in the far and shallow region.