Ulsan National Institute of Science and Technology · 工学
Professor Ngo Phong Nguyen's research lab specializes in advanced robust control methodologies for nonlinear and disturbed dynamical systems, with a strong focus on sliding mode control, disturbance observation, and finite-time stability. The lab develops innovative control frameworks—particularly continuous, nonsingular, and finite-time sliding mode controllers—tailored for complex engineering systems such as UAVs, rotary inverted pendulums, offshore cranes, and high-order integrator chains. Key research directions include disturbance observer design, chattering reduction, and robustness enhancement under matched and mismatched disturbances. The lab emphasizes practical implementation through fuzzy logic integration and multivariable control structures to ensure high precision and stability in real-world applications.
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This article proposes a continuous nonsingular terminal sliding-mode control with integral-type sliding surface (CNTSMC-ISS) framework for disturbed systems, in which we consider two types of finite-time controllers: the state feedback CNTSMC-ISS and the disturbance-observer-based CNTSMC-ISS. Compared with the existing sliding-mode controllers, the noteworthy contributions of two finite-time controllers in the proposed CNTSMC-ISS framework are the alleviation of the chattering phenomenon, the fa
This paper considers the stabilization problem for under-actuated rotary inverted pendulum systems (RotIPS) via a fuzzy-based continuous sliding mode control approach. Various sliding mode control (SMC) methods have been proposed for stabilizing the under-actuated RotIPS. However, there are two main drawbacks of these SMC approaches. First, the existing SMCs have a discontinuous structure; therefore, their control systems suffer from the chattering problem. Second, a complete proof of closed-loo
Abstract This article proposes a finite‐time disturbance observer‐based modified super‐twisting algorithm (FDO‐STA) for disturbed high‐order integrator‐chain systems under matched and mismatched disturbances. We first design a finite‐time observer for disturbance estimation, in which we show the finite‐time convergence of disturbance estimation errors to zero. Second, by employing the estimates of disturbances and their derivatives, a new dynamic sliding surface is derived, which ensures the fin
In this letter, we propose a multivariable disturbance observer-based finite-time sliding mode attitude control (MDOB-FT-SM-AC) for fixed-wing UAVs in the presence of both matched and mismatched disturbances. Compared with existing sliding mode attitude controllers, the significant improvements of the proposed MDOB-FT-SM-AC are the multivariable control structure, strong robustness, and high precision performance with continuous control input signal. In the proposed MDOB-FT-SM-AC, we first devel
Open sea loading/unloading cargos provides a potential solution to tack the problem related with port construction, expansion and congestion. This process involves a crane attached to a mobile harbor (MH) which can dynamically handle container from a large container anchored in deep water. The control objective during the operation is to maintain the payload in the desired position in the presence of ocean waves. This paper presents a robust control strategy for trajectory tracking and sway supp
In this paper, we propose the disturbance observer-based continuous finite-time sliding mode controller (DOBCSMC) for input-affine nonlinear systems in which additive matched and mismatched disturbances exist. The objective is to show the robustness and disturbance attenuation performance of the closed-loop system with the proposed DOBCSMC subjected to general classes of matched and mismatched disturbances. The proposed DOBCSMC consists of three main features: (i) the nonlinear finite-time distu
This article proposes finite-time continuous nonsingular terminal modified adaptive-gain super-twisting control (FT-CNT-MAG-STC) for the second-order disturbed systems. Compared with existing sliding-mode controllers, the noteworthy improvements of the proposed framework are the fast finite-time convergence, continuous control signal, ease-of-implementation feature, and relaxation of the assumption related to the information on the bounds of the disturbance and its derivative. In the proposed fr
A Fuzzy-PD control strategy for an offshore container crane is investigated in this study. The offshore crane is used to handle containers between a mega container ship (called the "mother ship") and a smaller ship (called the "mobile harbor"), which is equipped with container crane. The concept of the mobile harbor is a floating form that has the capability of transferring cargo to the local harbor from a large ship that is anchored in a nearby sea, thereby minimizing the port congestion and al
In this paper, we propose an observer-based super-twisting sliding mode control with fuzzy variable gains (OST-FVG) for general second-order nonlinear systems. First, the super-twisting observer with fuzzy variable gains is designed for state estimation, for which we show finite-time convergence of the estimation error to zero under the bounded disturbance. Then, together with the proposed observer, the sliding mode control with fuzzy variable gains is designed to ensure precise tracking control
We propose the neural-network based control (NNC) approach for rotary inverted pendulum (RIP). The control structure for RIP consists of two phases: (i) swing-up phase, which drives the pendulum up towards the desired upright position; and (ii) stabilization phase, which enables the pendulum to keep the desired upright position. In our paper, the swing-up controller is designed based on energy control approach with feedback linearization technique, where the corresponding control gain Kec is det
An adaptive sliding mode control scheme using radial basis function network (RBFN) for container cranes is investigated in this study. Here, a sliding surface is designed in such a way that sway motion of the payload is incorporated into the trolley dynamics. In addition, to relax the requirement of mathematical model in the design of a traditional sliding mode control (SMC) system, a neural network compensator, obtained by a radial basis function network and an adaption law, which approximates
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