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LQG Control Design for a Coupled Ballbot Dynamical System
Do Van Thach,Soon-Geul Lee 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10
Ballbot is an under-actuated mobile robot which possesses an omnidirectional mobility. It can maintain the self-balancing and transfer on a spherical ball. The position and orientation of the robot in a space can be determined by two sensors, an encoder and inertia measurement unit. The measurement and fusion data processes from sensors are inevitably effected noise. The noise profile presented in the system is modeled as an additive white gaussian noise (AWGN). In this paper, a linear quadratic gaussian (LQG) controller is developed for a 3D dynamics of a ballbot system. The LQG control design is a combination of linear optimal state-feedback controller and an optimal estimator. The optimal estimator is applied to estimate the outputs of the system which is assumed to be affected by AWGN. Numerical simulations are implemented to demonstrate the effectiveness of our approach for a coupled ballbot dynamics.
Design of an Energy-based Controller for a 2D Ball Segway
Do Van Thach,Pham Dinh Ba,Soon-Geul Lee 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10
A ball segway is a ballbot-type robot that has a car-like structure. It can move with three omnidirectional-wheel mechanisms to drive the ball while maintaining balance. To obtain stable balancing and transferring simultaneously of the 2D ball segway which is an underactuated system, a control law is designed based on energy method. The energy storage function is formulated to prove the passivity property of the system. Simulation results show the effectiveness of our approach.
Passivity-based Nonlinear Control for a Ballbot to Balance and Transfer
Van-Thach Do,이순걸,곽관웅 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.11
Ballbot is a robot that can transfer to a given position while maintaining a self-balanced upright posture on a spherical ball. This paper proposes a nonlinear control of a ballbot using three omnidirectional wheels in the driving mechanism. Assuming a small swing angle for balance, the full dynamics of the ballbot can be decomposed into three, which are two underactuated dynamics for two orthogonal vertical planes and the fully actuated dynamics for one horizontal plane. The passivity of closed-loop systems of vertical planes is derived from the modified potential energy function. The proposed controller is designed to control the balancing and transferring of the system based on Lyapunov theory and the passivity of the system. A proportional-derivative feedforward controller is applied to regulate the heading motion in the horizontal plane. Experiments are performed with a real ballbot system to validate the effectiveness of system modeling and to show the controllability of the proposed algorithm.
Thach Phan Van,Quang Khai Phan,Hoa Pham Quang,Gia Bao Pham,Ngoc Han Ngo Thi,Hong Tham Truong Thi,Anh Duy Do 한국식품영양과학회 2023 Preventive Nutrition and Food Science Vol.28 No.4
Kombucha is a widely consumed fermented tea beverage with diverse health benefits. In a previous study, we demonstrated that the use of cascara as a substrate results in a special kombucha beverage with high bioactivity. Traditional kombucha fermentation using a symbiotic culture of bacteria and yeast (SCOBY) can lead to inconsistent product quality because of the lack of control over microbial composition. We successfully isolated and identified yeast and bacteria, including Saccharomyces cerevisiae, Komagataeibacter rhaeticus, and Lactobacillus brevis that are appropriate starter cultures for cascara kombucha fermentation. We also demonstrated that a supplementation with lactic acid bacteria (LAB) and a mixture of S. cerevisiae and K. rhaeticus resulted in higher total polyphenol and flavonoid content of cascara kombucha compared with the traditionally fermented product using SCOBY as the inoculum. The free radical scavenging activity, inhibitory effects on α-amylase, tyrosinase activity, and antibacterial properties of cascara kombucha were also enhanced as a result of LAB supplement. These findings provide valuable insights into the controlled microbiological composition required for the fermentation of cascara kombucha, thereby ensuring consistent quality and enhanced bioactivity of the product. Further, the use of cascara as a substrate for kombucha production not only offers various health benefits and biological effects, but also repurposes by-products from the coffee industry, which contributes to sustainable development and is eco-friendly.
Do Bang,Pham Van Thach,Hiroyuki Awano,Hyunsoo Yang 한국물리학회 2020 Current Applied Physics Vol.20 No.2
We demonstrated domain wall (DW)-induced anomalous magnetoresistance (MR) generated in asymmetric and symmetric ferrimagnetic Tb/Co multilayered, and Tb–Co alloyed wires. The extraordinary Hall effect (EHE)- induced circulating currents in the vicinity of DWs between longitudinal voltage probes are assigned to the anomalous MR. A large anomalous MR ~1.5% was obtained in the asymmetric Tb/Co multilayered wire. The large MR can be attributed to an addition of spin Hall current with a long coherence length from an adjacent Pt layer. These results open new possibilities for the use of ferrimagnetic multilayered wires beyond multi-function devices.
Van Thach Phan,Do Anh Duy 한국미생물·생명공학회 2023 한국미생물·생명공학회지 Vol.51 No.4
Eradication of Helicobacter pylori infection is an essential strategy to decrease the risk of developing gastric cancer. However, the standard triple therapy has negative aspects associated with side effects and the emergence of antibiotic resistance. Therefore, alternative therapies are required to enhance the management of H. pylori infection effectively. In this study we examined the effect of emodin on the amelioration of inflammatory response due to H. pylori infection. Our results indicated that emodin treatment effectively decreased the expression of virulence genes, including sabA, vacA, cagL, cagA, sabA, and suppressed the adhesion ability of H. pylori to AGS cells. Emodin has been shown inhibitory effects on the inflammasome pathway through reductions in VacA translocation, lowering ROS stress, cleaved Caspase-1, NLRP3, and cleaved Gasdermin D levels, thereby lowered pyroptosis in infected cells. In summary, our study demonstrated that emodin has the ability to attenuate inflammation caused by H. pylori by modulating virulence gene expression and decreasing VacA translocation. Further study is required to evaluate the therapeutic efficacy of emodin in treating H. pylori infection and better understand the underlying mechanisms.
Coffee Husk By-Product as Novel Ingredients for Cascara Kombucha Production
( Bao Xuyen Nguyen Le ),( Thach Phan Van ),( Quang Khai Phan ),( Gia Bao Pham ),( Hoa Pham Quang ),( Anh Duy Do ) 한국미생물생명공학회 2024 Journal of microbiology and biotechnology Vol.34 No.3
Kombucha, a fermented beverage, is gaining popularity due to its numerous beneficial health effects. Various substrates such as herbs, fruits, flowers, and vegetables, have been used for kombucha fermentation in order to enhance the flavor, aroma, and nutritional composition. This study aims to investigate the potential suitability of cascara as a novel ingredient for kombucha production. Our findings suggested that cascara is a suitable substrate for kombucha production. Fermentation elevated the total phenolic and flavonoid content in cascara, which enhanced the antioxidant, antibacterial, and prebiotic characteristics of the product. Furthermore, the accumulation of acetic acid-induced the pH lowering reached 2.7 after 14 days of fermentation, which achieved the microbiological safety of the product. Moreover, 14 days of fermentation resulted in a balanced amalgamation of acidity, sweetness, and fragrance according to sensory evaluation. Our findings not only highlight the potential of cascara kombucha as a novel substrate for kombucha production but also contribute to repurposing coffee by-products, promoting environmentally friendly and sustainable agricultural development.
Long spin coherence length and bulk-like spin-orbit torque in ferrimagnetic multilayers
Yu, Jiawei,Bang, Do,Mishra, Rahul,Ramaswamy, Rajagopalan,Oh, Jung Hyun,Park, Hyeon-Jong,Jeong, Yunboo,Van Thach, Pham,Lee, Dong-Kyu,Go, Gyungchoon,Lee, Seo-Won,Wang, Yi,Shi, Shuyuan,Qiu, Xuepeng,Awano Springer Science and Business Media LLC 2019 Nature materials Vol.18 No.1