Backstepping Sliding Mode-based Model-free Control of Electro-hydraulic Systems

Hoai Vu Anh Truong,TRINH HOAI AN,안경관 사단법인 유공압건설기계학회 2022 드라이브·컨트롤 Vol.19 No.1

This paper presents a model-free system based on a framework of a backstepping sliding mode control (BSMC) with a radial basis function neural network (RBFNN) and adaptive mechanism for electro-hydraulic systems (EHSs). First, an EHS mathematical model was dedicatedly derived to understand the system behavior. Based on the system structure, BSMC was employed to satisfy the output performance. Due to the highly nonlinear characteristics and the presence of parametric uncertainties, a model-free approximator based on an RBFNN was developed to compensate for the EHS dynamics, thus addressing the difficulty in the requirement of system information. Adaptive laws based on the actor-critic neural network (ACNN) were implemented to suppress the existing error in the approximation and satisfy system qualification. The stability of the closed-loop system was theoretically proven by the Lyapunov function. To evaluate the effectiveness of the proposed algorithm, proportional-integrated-derivative (PID) and improved PID with ACNN (ACPID), which are considered two complete model-free methods, and adaptive backstepping sliding mode control, considered an ideal model-based method with the same adaptive laws, were used as two benchmark control strategies in a comparative simulation. The simulated results validated the superiority of the proposed algorithm in achieving nearly the same performance as the ideal adaptive BSMC.

Rule set of object-oriented classification using Landsat imagery in Donganh, Hanoi, Vietnam

Trinh Thi Hoai Thu,Pham Thi Lan,Tong Thi Huyen Ai 한국측량학회 2013 한국측량학회지 Vol.31 No.6

Rule set is an important step which impacts significantly on accuracy of object-oriented classification result. Therefore, this paper proposes a rule set to extract land cover from Landsat Thematic Mapper (TM) imageryacquired in Donganh, Hanoi, Vietnam. The rules were generated to distinguish five classes, namely river, pond,residential areas, vegetation and paddy. These classes were classified not only based on spectral characteristicsof features, but also indices of water, soil, vegetation, and urban. The study selected five indices, includinglargest difference index max.diff; length/width; hue, saturation and intensity (HSI); normalized differencevegetation index (NDVI) and ratio vegetation index (RVI) based on membership functions of objects. Overallaccuracy of classification result is 0.84% as the rule set is used in classification process.

Comprehensive Control Strategy and Verification for PEM Fuel Cell/Battery/Supercapacitor Hybrid Power Source

Hoai-An Trinh,Hoai Vu Anh Truong,Minh-Duc Pham,Tri Cuong Do,Hong-Hee Lee,Kyoung Kwan Ahn 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.2

Using renewable energy is becoming a new tendency for vehicular applications to reduce fossil fuel consumption and minimize greenhouse gas emissions. Well-known as an eco-friendly energy source, the proton exchange membrane fuel cell (PEMFC) is extensively used in hybrid power systems to achieve the objective of zero-emission and air protection. However, this type of fuel cell offers slow dynamics and cannot adapt to abrupt load variations when used as a primary energy source. To overcome this shortcoming, battery (BAT) and/or supercapacitor (SC) are supplemented as auxiliary sources. In this paper, an innovative energy management strategy (EMS) for a PEMFC/BAT/SC hybrid power source (HPS) is proposed to improve the accuracy of power distribution from energy sources to the load. In detail, according to different characteristics of energy sources, a frequency decoupling (FD) method is designed to determine the required currents for PEMFC, BAT, and SC based on the load power demand. Besides, an adaptive DC bus control loop is utilized to guarantee a stable DC output voltage by using the BAT. The proposed EMS is simulated in a MATLAB/Simulink environment and experimentally implemented with a real-time DSP TMS320F28379D controller board. Subsequently, a test bench of a 200 W PEMFC, 24 V–12 Ah battery, and 25 V–60 F supercapacitor is conducted for experimental validation. The obtained results show that the proposed EMS is effective to coordinate energy flows between the three used sources and enhance the fuel cell performance in a hybrid power system.

Rule set of object-oriented classification using Landsat imagery in Donganh, Hanoi, Vietnam

Trinh Thi Hoai Thu,Pham Thi Lan,Tong Thi Huyen Ai 한국측량학회 2013 한국측량학회지 Vol.31 No.6-2

Rule set of object-oriented classification using Landsat imagery in Donganh, Hanoi, Vietnam

Thu, Trinh Thi Hoai,Lan, Pham Thi,Ai, Tong Thi Huyen Korean Society of Surveying 2013 한국측량학회지 Vol.31 No.6

Rule set is an important step which impacts significantly on accuracy of object-oriented classification result. Therefore, this paper proposes a rule set to extract land cover from Landsat Thematic Mapper (TM) imagery acquired in Donganh, Hanoi, Vietnam. The rules were generated to distinguish five classes, namely river, pond, residential areas, vegetation and paddy. These classes were classified not only based on spectral characteristics of features, but also indices of water, soil, vegetation, and urban. The study selected five indices, including largest difference index max.diff; length/width; hue, saturation and intensity (HSI); normalized difference vegetation index (NDVI) and ratio vegetation index (RVI) based on membership functions of objects. Overall accuracy of classification result is 0.84% as the rule set is used in classification process.

수소 트랙터의 에너지 관리 전략 개발

찐호이안 ( Hoai-an Trinh ),유재웅 ( Jae Ung Yu ),안지환 ( Jee Hwan Ahn ),권태민 ( Tae Min Kwon ),안경관 ( Kyoung Kwan Ahn ) 한국농업기계학회 2023 한국농업기계학회 학술발표논문집 Vol.28 No.2

오늘날 전기자동차, 건설기계 또는 농기계와 같은 종류의 기계에 대한 재생 동력원의 구현은 기존의 내연기관을 대체하고 온실가스 배출을 줄이기 위해 점점 더 많이 사용되고 있다. 최근, 양성자 교환막 연료전지(PEMFC)는 전통적인 에너지원을 대체하여 수소 트랙터를 개발하는데 사용될 수 있는 주요하고 실행 가능한 녹색 에너지원으로 주목받고 있다. 또한, 에너지 관리 전략(EMS) 개발은 다른 작업 조건에서 부하 전력 수요를 만족시키고 수소 트랙터 내부의 동력원 간의 적합한 전력 분배를 보장하기 위한 중요한 요건이다. 이러한 목적을 위해, 본 논문에서는 PEMFC 시스템으로 구동되는 수소 트랙터와 Li-ion 배터리 팩과 슈퍼커패시터 뱅크로 구성된 에너지 저장 장치에 대한 최적의 EMS를 제안한다. 본 시스템에서는 부하 전력 적응을 보장할 뿐만 아니라 수소 소모를 최소화하고 연료전지 스택의 작동 효율을 향상시키기 위해 등가 소비 최소화 전략을 제안한다. 마지막으로, 제안된 전략과 이전 전략의 효과를 다른 시나리오에서 검증하고 비교하기 위해 비교 시뮬레이션을 수행한다.

Elucidation of HpdR – a 3-hydroxipropionic acid responsive transcription activator protein in Pseudomonas denitrificans

Trinh THI NGUYEN,Satish KUMAR AINALA,Nam HOAI NGUYEN,Yeonhee KIM,Sunghoon PARK 한국생물공학회 2016 한국생물공학회 학술대회 Vol.2016 No.4

In vivo Characterization of the Inducible Promoter System of 3-hydroxypropionic Dehydrogenase in Pseudomonas denitrificans

Trinh Thi Nguyen,Nam Hoai Nguyen,김연희,김중래,박성훈 한국생물공학회 2021 Biotechnology and Bioprocess Engineering Vol.26 No.4

Here, we characterized a gene expression system induced by 3-hydroxypropionic acid (3-HP) in Pseudomonas denitrificans. The system consists of a putative LysR-type transcriptional regulator (LTTR) encoded by hpdR and a LTTR-responsive promoter that positively controls the expression of hpdH, encoding 3-HP dehydrogenase in the presence of 3-HP. In the hpdH-responsive promoter region, two operators exhibiting dyad symmetry and designated O1 and O2 and centered at the -73 and -30 positions, respectively, were located upstream of the hpdH transcription start site. When either O1, O2, or both regions were mutated, the inducibility by the HpdR-3-HP complex was significantly reduced or completely removed, indicating that both sites are required for transcriptional activation. The HpdR protein and its operator sites on hpdH were highly specific for each other, and did not engage in cross-talk with another similar 3-HP-inducible system that is also present in P. denitrificans. This 3-HP-inducible promoter system should be useful in developing biosensors for 3-HP, and/or dynamic gene expression systems for metabolic engineering purposes.

Assessment of Wind Turbine Generators on Reliability of Distribution Network

Trinh Trong Chuong,Nguyen Van Hung,Nguyen Hoai Nam 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.6

Wind turbine generators (WTG) is predicted to play a prominent role in the electric power systems of the future. Connection of wind turbine generators to the distribution network increases power sources and therefore increases reliability of distribution network. Assessment of reliability of distribution network connected to wind turbine generators based on two state model yields big errors due to dependence of wind source capacity on wind speed which is a variable value. For more accurate assessment results, the article proposes to utilize multi-stage model of wind source reliability and switch section partitioning based on reliability on distribution network.

TTG1-mediated flavonols biosynthesis alleviates root growth inhibition in response to ABA.

Nguyen, Hoai Nguyen,Kim, Jun Hyeok,Hyun, Woo Young,Nguyen, Ngoc Trinh,Hong, Suk-Whan,Lee, Hojoung Springer 2013 Plant cell reports Vol.32 No.4

<P>Our results demonstrate that the flavonoids biosynthetic pathway can be effectively manipulated to confer enhanced plant root growth under water-stress conditions. Abscisic acid (ABA) is one of most important phytohormones. It functions in various processes during the plant lifecycle. Previous studies indicate that ABA has a negative effect on root growth and branching. Auxin is another key plant growth regulator that plays an essential role in plant growth and development. In contrast to ABA, auxin is a positive regulator of root growth and development at low concentrations. This study was performed to help understand whether flavonoids can suppress the effect of ABA on lateral root growth. The recessive TRANSPARENT TESTA GLABRA 1 (ttg1) mutant was characterized on ABA and sucrose treatments. It was determined that auxin mobilization could be altered by modifying flavonoids biosynthesis, which resulted in alterations of root architecture in response to ABA treatment. Moreover, transgenic TTG1-overexpression (TTG1-OX) seedlings exhibited enhanced root length and lateral root number compared to wild-type seedlings grown under normal or stress conditions. Genetic manipulation of the flavonoids biosynthetic pathway could therefore be employed successfully for the improvement of plant root systems by overcoming the inhibition of ABA and some abiotic stresses.</P>