Adaptive Reinforcement Learning Strategy with Sliding Mode Control for Unknown and Disturbed Wheeled Inverted Pendulum

Phuong Nam Dao,Yen-Chen Liu 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.2

This paper develops a novel adaptive integral sliding-mode control (SMC) technique to improve the tracking performance of a wheeled inverted pendulum (WIP) system, which belongs to a class of continuous time systems with input disturbance and/or unknown parameters. The proposed algorithm is established based on an integrating between the advantage of online adaptive reinforcement learning control and the high robustness of integral sliding-mode control (SMC) law. The main objective is to find a general structure of integral sliding mode control law that can guarantee the system state reaching a sliding surface in finite time. An adaptive/approximate optimal control based on the approximate/adaptive dynamic programming (ADP) is responsible for the asymptotic stability of the closed loop system. Furthermore, the convergence possibility of proposed output feedback optimal control was determined without the convergence of additional state observer. Finally, the theoretical analysis and simulation results validate the performance of the proposed control structure.

Synthesis, bioevaluation and docking study of 5-substitutedphenyl-1,3,4-thiadiazole-based hydroxamic acids as histone deacetylase inhibitors and antitumor agents

Nam, Nguyen-Hai,Huong, Tran Lan,Dung, Do Thi Mai,Dung, Phan Thi Phuong,Oanh, Dao Thi Kim,Park, Sang Ho,Kim, Kyungrok,Han, Byung Woo,Yun, Jieun,Kang, Jong Soon,Kim, Youngsoo,Han, Sang-Bae Informa UK Ltd. 2014 Journal of enzyme inhibition and medicinal chemist Vol.29 No.5

<P>Since the first histone deacetylase (HDAC) inhibitor (Zolinza®, widely known as suberoylanilide hydroxamic acid; SAHA) was approved by the Food and Drug Administration for the treatment of T-cell lymphoma in 2006, the search for newer HDAC inhibitors has attracted a great deal of interest of medicinal chemists worldwide. As a continuity of our ongoing research in this area, we designed and synthesized a series of 5-substitutedphenyl-1,3,4-thiadiazole-based hydroxamic acids as analogues of SAHA and evaluated their biological activities. A number of compounds in this series, for example, <I>N<SUP>1</SUP></I>-hydroxy-<I>N</I><SUP>8</SUP>-(5-(2-chlorophenyl)-1,3,4-thiadiazol-2-yl)octandiamide (<B>5b</B>), <I>N<SUP>1</SUP></I>-hydroxy-<I>N</I><SUP>8</SUP>-(5-(3-chlorophenyl-1,3,4-thiadiazol-2-yl)octandiamide (<B>5c</B>) and <I>N<SUP>1</SUP></I>-hydroxy-<I>N</I><SUP>8</SUP>-(5-(4-chlorophenyl)-1,3,4-thiadiazol-2-yl)octandiamide (<B>5d</B>), were found to possess potent anticancer cytotoxicity and HDAC inhibition effects. Compounds <B>5b</B>-<B>d</B> were generally two- to five-fold more potent in terms of cytotoxicity compared to SAHA against five cancer cell lines tested. Docking studies revealed that these hydroxamic acid displayed higher affinities than SAHA toward HDAC8.</P>

Metagenomic analysis of bacterial community structure and diversity of lignocellulolytic bacteria in Vietnamese native goat rumen

Do, Thi Huyen,Dao, Trong Khoa,Nguyen, Khanh Hoang Viet,Le, Ngoc Giang,Nguyen, Thi Mai Phuong,Le, Tung Lam,Phung, Thu Nguyet,Straalen, Nico M. van,Roelofs, Dick,Truong, Nam Hai Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.5

Objective: In a previous study, analysis of Illumina sequenced metagenomic DNA data of bacteria in Vietnamese goats' rumen showed a high diversity of putative lignocellulolytic genes. In this study, taxonomy speculation of microbial community and lignocellulolytic bacteria population in the rumen was conducted to elucidate a role of bacterial structure for effective degradation of plant materials. Methods: The metagenomic data had been subjected into Basic Local Alignment Search Tool (BLASTX) algorithm and the National Center for Biotechnology Information non-redundant sequence database. Here the BLASTX hits were further processed by the Metagenome Analyzer program to statistically analyze the abundance of taxa. Results: Microbial community in the rumen is defined by dominance of Bacteroidetes compared to Firmicutes. The ratio of Firmicutes versus Bacteroidetes was 0.36:1. An abundance of Synergistetes was uniquely identified in the goat microbiome may be formed by host genotype. With regard to bacterial lignocellulose degraders, the ratio of lignocellulolytic genes affiliated with Firmicutes compared to the genes linked to Bacteroidetes was 0.11:1, in which the genes encoding putative hemicellulases, carbohydrate esterases, polysaccharide lyases originated from Bacteroidetes were 14 to 20 times higher than from Firmicutes. Firmicutes seem to possess more cellulose hydrolysis capacity showing a Firmicutes/Bacteroidetes ratio of 0.35:1. Analysis of lignocellulolytic potential degraders shows that four species belonged to Bacteroidetes phylum, while two species belonged to Firmicutes phylum harbouring at least 12 different catalytic domains for all lignocellulose pretreatment, cellulose, as well as hemicellulose saccharification. Conclusion: Based on these findings, we speculate that increasing the members of Bacteroidetes to keep a low ratio of Firmicutes versus Bacteroidetes in goat rumen has resulted most likely in an increased lignocellulose digestion.

Some characters of bacterial cellulases in goats' rumen elucidated by metagenomic DNA analysis and the role of fibronectin 3 module for endoglucanase function

Nguyen, Khanh Hoang Viet,Dao, Trong Khoa,Nguyen, Hong Duong,Nguyen, Khanh Hai,Nguyen, Thi Quy,Nguyen, Thuy Tien,Nguyen, Thi Mai Phuong,Truong, Nam Hai,Do, Thi Huyen Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.5

Objective: Fibronectin 3 (FN3) and immunoglobulin like modules (Ig) are usually collocated beside modular cellulase catalytic domains. However, very few researches have investigated the role of these modules. In a previous study, we have sequenced and analyzed bacterial metagenomic DNA in Vietnamese goats' rumen and found that cellulase-producing bacteria and cellulase families were dominant. In this study, the properties of modular cellulases and the role of a FN3 in unique endoglucanase belonging to glycosyl hydorlase (GH) family 5 were determined. Methods: Based on Pfam analysis, the cellulases sequences containing FN3, Ig modules were extracted from 297 complete open reading frames (ORFs). The alkaline, thermostability, tertiary structure of deduced enzymes were predicted by AcalPred, TBI software, Phyre2 and Swiss models. Then, whole and truncated forms of a selected gene were expressed in Escherichia coli and purified by His-tag affinity column for assessment of FN3 ability to enhance enzyme activity, solubility and conformation. Results: From 297 complete ORFs coding for cellulases, 148 sequences containing FN3, Ig were identified. Mostly FN3 appeared in 90.9% beta-glucosidases belonging to glycosyl hydrolase family 3 (GH3) and situated downstream of catalytic domains. The Ig was found upstream of 100% endoglucanase GH9. Rarely FN3 was seen to be situated downstream of X domain and upstream of catalytic domain endoglucanase GH5. Whole enzyme (called XFN3GH5 based on modular structure) and truncate forms FN3, XFN3, FN3GH5, GH5 were cloned in pET22b (+) and pET22SUMO to be expressed in single and fusion forms with a small ubiquitin-related modifier partner (S). The FN3, SFN3 increased GH5 solubility in FN3GH5, SFN3GH5. The SFN3 partly served for GH5 conformation in SFN3GH5, increased modules interaction and enzyme-soluble substrate affinity to enhance SXFN3GH5, SFN3GH5 activities in mixtures. Both SFN3 and SXFN3 did not anchor enzyme on filter paper but exfoliate and separate cellulose chains on filter paper for enzyme hydrolysis. Conclusion: Based on these findings, the presence of FN3 module in certain cellulases was confirmed and it assisted for enzyme conformation and activity in both soluble and insoluble substrate.

An Adaptive Backstepping Trajectory Tracking Control of a Tractor Trailer Wheeled Mobile Robot

NGUYEN THANH BINH,Nguyen Anh Tung,Dao Phuong Nam,Nguyen Hong Quang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.2

The considered Tractor Trailer Wheeled Mobile Robot (TTWMR) is type of Mobile Robot including amaster robot – Tractor and slave robots – Trailers which moves along Tractor to track a given desired trajectory. Themain difficulties of the stabilization and the tracking control of TTWMR are due to nonlinear and underactuatedsystems subjected to nonholonomic constraints. In order to overcome these problems, firstly, we develop the modelof TTWMR and transform the tracking error model to the triangular form to propose a control law and an adaptivelaw. Secondly, the varying time state feedback controllers are designed to generate actuator torques by usingBackstepping technique and Lyapunov direct’s method, in that these are able to guarantee the stability of the wholesystem including kinematics and dynamics. In addition, the Babarlat’s lemma is used to prove that the proposedtracking errors converge to the origin and the proposed adaptive law is carried on to tackle unknown parameterproblem. The simulations are implemented to demonstrate the effective performances of the proposed adaptive lawand the proposed control law.

Online Actor-critic Reinforcement Learning Control for Uncertain Surface Vessel Systems with External Disturbances

Van Tu Vu,Quang Huy Tran,Thanh Loc Pham,Phuong Nam Dao 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.3

This article addresses a trajectory tracking control approach for an uncertain surface vessel using the new cascade structure of adaptive reinforcement learning (ARL) algorithm and kinematic controller, feed-forward term. Since a surface vessel is decoupled by kinematic sub-system and dynamic sub-system, the cascade control system is an ideal method for obtaining the tracking problem. In the proposed control structure, the dynamic control loop is designed to be the optimized method of the corresponding dynamic sub-system and the kinematic control loop is implemented by a nonlinear controller combining with feed-forward term. The online actor-critic architecture is considered in ARL algorithm to overcome the challenge of solving the Hamilton-Jacobi-Bellman (HJB) equation. Additionally, the proposed controller is able to handle the difficulty of the non-autonomous optimal control problem by designing the ARL technique for the corresponding system with a small number of state variables. Based on theoretical analysis, the ARL based control design has been made to guarantee the uniformly ultimately bounded (UUB) stability of the closed system. Finally, the simulation results are illustrated to verify the effectiveness of the proposed control scheme.