Balancing and Translation Control of a Ball Segway That a Human Can Ride

Pham Dinh Ba,Soon-Geul Lee,Seungyup Back,Jaejun Kim,Min Kyoung Lee 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

A ball segway, a ballbot-type robot that can carry a person is developed. The robot is of a sufficient size and has a car-like structure mounted on a single spherical tire with a seat that a human can ride. Based on the kinematic model of the ball segway, the full 3D dynamic model is simplified and decoupled into two orthogonal 2D dynamic models, where one is related sagittal motion and the other is related frontal motion, based on Lagrange equation and decoupling method. After linearizing dynamic model, two-loop control system is applied to each plane for control balancing, station keeping and transferring itself from point to point. Balancing and transferring performance of the ball segway is evaluated by experiments.

Hierarchical Sliding Mode Control for a 3D Ballbot that is a Class of Second-order Under-actuated System

Pham Dinh Ba,Hoang Quoc Dong,Nguyen Lan Huong,Soon-Geul Lee 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

This paper proposes a hierarchical sliding mode controller for a three-dimensional ballbot in an extremely complicated operation of three omni-directional wheels, a ball, and body. Three ball motors simultaneously drive four outputs comprising ball motion and two tilt angles of the body. Simulation tests are performed to investigate the controller qualities. The proposed controller asymptotically stabilizes and consistently maintains system response.

Partial Feedback Linearization Double-loop Control for a Pseudo-2D Ridable Ballbot

Dinh Ba Pham,원인식,Soon-Geul Lee 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.5

A ridable ballbot has unstable underactuated dynamics with nonholonomic velocity constraints and input coupling case. Such a robot can carry people and move in any direction on the floor. In this study, a pseudo-2D dynamic model of the ridable ballbot is derived. An improved nonlinear double-loop control system combined with the partial feedback linearization (PFL) technique is proposed for the ridable ballbot, which allows it to balance and transfer. Feedforward compensation is added to the controller to consider uncertainties, friction, and disturbances. Numerical simulations and experiments show the validity of the PFL double-loop control based on the pseudo-2D dynamic model.

Kinematic Modeling of Spherical Rolling Robots with a Three-Omnidirectional-Wheel Drive Mechanism

Pham Dinh Ba,Quoc Dong Hoang,Soon-Geul Lee,Thanh Hai Nguyen,Xuan Quang Duong,Boi Chau Tham 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10

The spherical rolling robot (SRR) is an underactuated system with nonholonomic constraints. The proposed drive mechanism for the mobile robot is comprised of three omnidirectional wheels to make the omnidirectional movement of the robot on the floor. The kinematic model of the SRR is derived via nonholonomic constraints. Numerical simulation is analyzed. Results indicate that the robot can track the desired trajectory and maintain its balance stably at the same time.

Double-loop Control with Hierarchical Sliding Mode and Proportional Integral Loop for 2D Ridable Ballbot

Dinh Ba Pham,Jaejun Kim,이순걸,곽관웅 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.9

In this study, we propose a nonlinear double-loop control system for a ridable ballbot. An improved nonlinear double-loop control technique based on double-loop control scheme and sliding mode technology is used, and the inner-loop consists of proportional–integral feedback plus feedforward control. A sliding mode control enables the ridable ballbot to balance and transfer on the floor. Feedforward compensation has been added for the stability of the ballbot. As a result, the control system can stabilize all state variables of the ballbot system despite the uncertainties of the system parameters such as model, friction, and external disturbances, and relatively large body inertia. Experiments demonstrate the effectiveness of the proposed control system and the performance validation of the nonlinear double-loop control.

Aggregated Hierarchical Sliding Mode Control for a Spatial Ridable Ballbot

Dinh Ba Pham,이순걸 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.9

In this study, the dynamical model of a ridable ballbot system is investigated to derive a nonlinear model that can describe the spatial dynamics of the mechatronic system by use of a set of differential equations. An aggregated hierarchical sliding mode control is proposed for a spatial ridable ballbot which is a class of multiple-input and multiple-output underactuated systems funder input coupling case and nonholonomic velocity constraints. The spatial ridable ballbot system is divided into ball and body subsystems. The hierarchical structure of the sliding mode surfaces (SMSs) is designed on the basis of the two subsystems as follows. First, the SMS of every subsystem is defined. Then the SMS of each subsystem is defined as the first layer SMS. The first layer SMS is used to construct the second layer SMS with the SMS of the other subsystem. This process continues until the SMS of all subsystems is included. The total control law is deduced from the hierarchical structure. Asymptotic stability of the control system is theoretically proven by Barbalat’s lemma in the ideal of Lyapunov theory. Simulation and experimental results indicate the validity of the proposed controller.

Antimicrobial efficacy of extracts and constituents fractionated from <i>Rheum tanguticum</i> Maxim. ex Balf. rhizomes against phytopathogenic fungi and bacteria

Pham, Duong Quang,Ba, Duong Thi,Dao, Nga Thu,Choi, Gyung Ja,Vu, Thuy Thu,Kim, Jin-Cheol,Giang, Thi Phuong Ly,Vu, Hoang Dinh,Le Dang, Quang Elsevier 2017 INDUSTRIAL CROPS AND PRODUCTS Vol.108 No.-

<P><B>Abstract</B></P> <P>The antimicrobial efficacies of extracts and constituents fractionated from <I>Rheum tanguticum</I> rhizomes were evaluated by using <I>in vitro</I> and <I>in vivo</I> bioassay against seven phytopathogenic fungi and ten pathogenic bacteria, respectively. Dichloromethane and ethyl acetate soluble extracts derived from <I>R. tanguticum</I> rhizomes effectively controlled plant diseases caused by five fungi <I>Magnaporthe oryzae</I>, <I>Blumeria graminis</I> f. sp<I>. hordei, Colletotrichum coccodes, Phytophthora infestans,</I> and <I>Puccinia recondita</I> in <I>in vivo</I> whole plant bioassay. In addition, these extracts showed strong inhibitory activity against the bacterial growth of <I>Acidovorax avenae</I> subsp. <I>cattlyae</I> (Aac), <I>Clavibacter michiganensis</I> subsp. <I>michiganensis</I>, <I>Xanthomonas arboricola</I> pv. <I>pruni</I> (Xap), and <I>Pseudomonas syringae</I> pv. <I>actinidiae</I> (Psa), with MIC values ranging from 125 to 250μg/mL. The active extracts of <I>R. tanguticum</I> rhizomes were fractionated by using various and repeated chromatographic techniques to yield seven constituents that included three anthraquinones and four stilbenes. Notably, at concentrations ranging from 75 to 300μg/mL, physcion (<B>DH03</B>) and chrysophanol (<B>DH04</B>) were significantly effective in suppressing the development of barley powdery mildew (BPM) caused by <I>B. graminis</I> f. sp. <I>hordei,</I> with control values from 80 to 96.7%. Moreover, stilbenes rhapontigenin (<B>DH02</B>) and desoxyrhapontigenin (<B>DH05</B>) had a broad spectrum and potent activity against phytopathogenic bacteria; <B>DH05</B> effectively inhibited the bacterial growth of Aac, <I>Burkholderia glumae</I> and Psa at MICs ranging from 38 to 150μg/mL. In this paper, we report their antibacterial activity for the first time. The botanical materials containing anthraquinones and stilbenes were active against both phytopathogenic fungi and bacteria. These results suggested that <I>R. tanguticum</I> rhizomes could be used as a new source of antimicrobial substances for developing a botanical fungicide and bactericide to control plant diseases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>R. tanguticum</I> extracts exhibited activity against phytopathogenic fungi and bacteria. </LI> <LI> Seven anthraquinones and stilbenes from <I>R. tanguticum</I> were isolated and identified. </LI> <LI> <I>In vivo</I> antifungal activity of botanicals was evaluated by the whole plant bioassay. </LI> <LI> The isolated stilbenes effectively inhibited the growth of phytopathogenic bacteria. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Nonlocal Mindlin plate theory with the application for vibration and bending analysis of nanoplates with the flexoelectricity effect

Pham Ba Khien,Du Dinh Nguyen,Abdelouahed Tounsi,Bui Van Tuyen Techno-Press 2024 Advances in nano research Vol.16 No.1

This work is the first of its kind to integrate Mindlin's theory with analytical methods in order to produce an exact solution to a specific vibration issue as well as a bending problem involving a nanoplate that is supported by a viscoelastic foundation. The plate is exposed to the simultaneous effects of a compressive load in the plate plane and a force operating perpendicular to the plane of the nanoplate. In addition, the flexoelecity effect is included into the plate. The strain gradient component is taken into consideration while calculating the plate equilibrium equation using the nonlocal theory and Hamilton's principle. The free vibration and static responses of the nanoplate seem to be both real and imaginary components because of the appearance of the viscoelastic drag coefficient of the viscoelastic foundation. This study also shows that when analyzing the mechanical response for nanostructure, taking into account the flexoelectricity effect and the influence of the nonlocal parameter, the results will be completely different from the case in which this parameter is ignored. This indicates that it is vital to take into consideration the effects of nonlocal parameters on the nanosheet structure while also taking into consideration the effect of flexoelectricity.

An Empirical Study of Perceived Organizational Support and Affective Commitment in the Logistics Industry

HOA, Nguyen Dinh,NGAN, Pham Thi Hong,QUANG, Nguyen Minh,THANH, Vu Ba,QUYEN, Huynh Vo Thuc Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.8

The study examines the impact of organizational rewards, procedure justice, and perceived supervisor support on perceived organizational support, and examine the impact of perceived organizational support on affective commitment to the organization in the logistic enterprises as well. Quantitative research is applied to measure relationships by regression analysis with SPSS. The research data was collected by convenient method from 180 employees who work in different departments in the logistics industry. The study results in the model 1 found that organizational rewards, procedure justice, and perceived supervisor support have a positive relationship to the perceived organizational support. The study results in the model 2 also found that perceived organizational support has strong impact on the affective commitment to the organization. The study results contribute to both management theory and management practice. For the management theory aspect, the authors suggest that perceived organizational support should be considered the key antecedent of affective commitment about which researchers should pay more attention as a concept. Based on the research results, the authors also recommend for the management practice that managers should pay attention to the implementation of rewards, procedure justice, and supervisor support to increase the perceived organizational support and affective commitment in the logistic enterprises.

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.