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Finite-time Adaptive Gain Terminal Sliding Mode Control for Uncertain Ball and Beam System Based on Honey Badger-RBF Algorithm
(2025-08-01)
Jitkhamhaeng, Ponpawit
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Wongvanich, Napasool
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Tangsrirat, Worapong
This paper presents a finite-time fast terminal sliding mode control (FTSMC) for an uncertain ball and beam system (BBS) to achieve desired states or corrections within a finite time frame, which is a crucial aspect of the control system performance. An integral-based parameter identification method was first derived to give a nominal model of the BBS before designing the FTSMC. A robustness analysis reveals that this method could robustly achieve identification within a bound. The designed FTSMC was enhanced through the use of the honey badger algorithm (HBA), which was combined with the normal radial basis function neural network (RBF-NN) to create an HBA-RBF network. Experimental results show that the proposed HBA-RBF network-based finite-time adaptive terminal sliding mode controller improved the response rate, as well as reduced the risk of chattering. The HBA-RBF network not only enhances controller performance but also ensures robust and reliable control, making it a promising approach for handling uncertainties in control systems.
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Observer-less Fixed-Time Speed Control For Permanent Magnet Synchronous Motors with matched-mismatched disturbances
(2025-01-01)
Cholahan, Varin
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Wongvanich, Napasool
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Tangsrirat, Worapong
This paper presents a state-dependent Variable Exponent Coefficient Sliding Mode Control (VECFSMC) By inducing fixed-time stability analysis, the proposed state-dependent sliding surface provides not only system stability but also a quick response in a fixed period of time as well as counteract with matched and mismatched disturbances. The proposed sliding mode control strategy does not use observers to estimate the disturbances. The designed sliding mode surface possesses robustness properties which is sufficient to cope with both matched and mismatch disturbances in a period of fixed time. Firstly, the mathematical model of permanent magnet synchronous motor and the mathematical background of variable exponent coefficient are demonstrated theoretically. Secondly, the state-dependent sliding surface with variable exponent coefficient is designed. The controller that can manipulate both the speed of PMSM and matched-mismatched disturbances is constructed. Lyapunov function is applied to assess the stability of the proposed method. Finally, a numerical simulation with PMSM drive shows fast convergence, good robustness against both matched and mismatched disturbances. The proposed fixed-time controller with this observer-less method offers high efficiency and offers not too complicated control solution comparing to the other fixed-time and finite-time methods with a small number of parameters.
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Robust Variable Exponent Fixed-Time Speed Control of PMSMs Based on a Fixed-Time Sliding Mode Observer
(2025-01-01)
Cholahan, Varin
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Wongvanich, Napasool
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Tangsrirat, Worapong
This paper presents a state-dependent variable exponent coefficient sliding mode control (VECFSMC). By inducing fixed-time stability analysis, the proposed state-dependent sliding surface provides not only system stability but also a quick response in a fixed period of time. To enhance the controller's ability to direct state trajectories along the sliding surface manifold towards equilibrium and attain the desired outputs despite the presence of disturbances, a fixed-time sliding-mode observer (FTSMO) has been created. The approach is assessed by Lyapunov stability analysis. Eventually, a numerical simulation of composited fixed-time Controller and fixed time Observer evidently shows fast convergence, high robustness against lump disturbances. The proposed technique, along with the fixed-time observer, achieves global fixed-time stabilization and offers straightforward implementation compared to other fixed-time methods, requiring the tuning of fewer parameters.
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Potential jet-space based practical identifiability and integral backstepping sliding mode control of heat exchanger
(2025-01-01)
Sitthisuk, Nichaphat
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Wongvanich, Napasool
This work develops the minimal modeling methodology for modeling and control of the liquid-liquid heat exchanger system. An application of the potential jet space theory is firstly presented, where the cross-convection model of the heat exchanger dynamics is prolonged onto the potential jet space to generate the input-output equations that are written in terms of integrals of the measured data. This integral based input-output equation then facilitates the parameter estimation without extensive computational loading demands. The linear potential jet space model was first applied to the measured data, and extended to capture the time delay effect in the measurement. An integral backstepping sliding mode controller was also designed. The delay model was shown to give a tracking temperature error to within 0.0004 degrees, with a mean integral absolute error (ITAE) of around 0.27, even with heavy parameter changes.
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Practical Robust Fixed-Time Speed Control of Permanent Magnet Synchronous Motors with Adaptive Disturbance Rejection
(2025-01-01)
Wongvanich, Napasool
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Cholahan, Varin
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Tangsrirat, Worapong
The research presents an adaptive fixed-time speed controller of Permanent Magnet Synchronous Motors for a second-order nonlinear systems, grounded in practical fixed-time stability (CFTSMC). This approach employs a sliding mode surface with constant exponent coefficient designed to circumvent singularities and achieve a rapid convergence. Compared to more complex fixed-time controller, this method offers ease to implement. In addition, the maximum limits for control inputs are simply determined to avoid saturation problems. Subsequently, the stability of nonlinear speed control system is analyzed using well-kwon nonlinear Lyapunov technique. An adaption algorithm called adaptive disturbance rejection (ADR), is incorporated with a smooth tanh function to mitigate overall disturbances and chattering, thereby ensuring that the tracking error stays within a bounded residual region. Ultimately, numerical simulations are provided to demonstrate the efficacy of both controller and disturbance rejection approach.
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A Constant Exponent Coefficient Fixed-Time Control For Voltage Regulating DC-DC Converter
(2025-01-01)
Cholahan, Varin
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Wongvanich, Napasool
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Tangsrirat, Worapong
This research examines the voltage regulation capabilities of a DC-DC converter that employs the Fixed-Time control (FTSMC) method, incorporating a Constant Exponent Coefficient reaching law technique. The suggested approach is characterized by its simplicity, stability, and robustness, especially in the face of significant variations in load demands and input voltage. A state-space average dynamical model (SSA) is formulated. Initially, Continuous Conduction Mode (CCM) is established, followed by the development of the more advanced Discontinuous Conduction Mode (DCM). The nonlinear model considers two variables associated with the controlled voltage and the inductor coil current as state variables. To estimate unknown parameters, the feedback linearization method is applied. The dynamic system's output voltage is regulated using a Fixed-Time control technique. The proposed control system's stability is validated through the application of Lyapunov's theorem, which guarantees closed-loop stability. Finally, the simulation outcomes indicate the performance regulation relative to conventional linear controllers.
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A Novel Practical Fixed-Time Speed Control of Permanent Magnet Synchronous Motors with Input Saturation
(2025-01-01)
Cholahan, Varin
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Wongvanich, Napasool
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Tangsrirat, Worapong
In this article, we focus on a control problem for the speed control of a permanent magnet synchronous motor (PMSM). An antisaturation adaptive fixed-time nonsingular sliding mode control (AFFTNSM) with disturbance estimation compensation is designed for a class of second-order nonlinear systems to improve PMSM system performance. Firstly, a novel fast fixed-time nonsingular sliding mode surface is chosen based on the error dynamic equation. Then, a practical fixed-time sliding mode control algorithm is proposed where the stability of the proposed controller is demonstrated to show the convergence of the velocity tracking error to a neighborhood of the origin in fixed-time. The implementation of feedforward compensation of disturbance enhances the dynamic performance of the fast fixed-time nonsingular sliding mode control rule, resulting in reduced chattering phenomena. Numerical simulation results are provided to verify the efficiency of the proposed method.
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Optimal Control Strategy of a Mathematical Model for the Fifth Wave of COVID-19 Outbreak (Omicron) in Thailand
(2024-01-01)
Lamwong, Jiraporn
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Wongvanich, Napasool
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Tang, I. Ming
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Pongsumpun, Puntani
The world has been fighting against the COVID-19 Coronavirus which seems to be constantly mutating. The present wave of COVID-19 illness is caused by the Omicron variant of the coronavirus. The vaccines against the five variants (α, β, γ, δ, and ω) have been quickly developed using mRNA technology. The efficacy of the vaccine developed for one of the strains is not the same as the efficacy of the vaccine developed for the other strains. In this study, a mathematical model of the spread of COVID-19 was made by considering asymptomatic population, symptomatic population, two infected populations and quarantined population. An analysis of basic reproduction numbers was made using the next-generation matrix method. Global asymptotic stability analysis was made using the Lyapunov theory to measure stability, showing an equilibrium point’s stability, and examining the model with the fact of COVID-19 spread in Thailand. Moreover, an analysis of the sensitivity values of the basic reproduction numbers was made to verify the parameters affecting the spread. It was found that the most common parameter affecting the spread was the initial number in the population. Optimal control problems and social distancing strategies in conjunction with mask-wearing and vaccination control strategies were determined to find strategies to give better control of the spread of disease. Lagrangian and Hamiltonian functions were employed to determine the objective function. Pontryagin’s maximum principle was employed to verify the existence of the optimal control. According to the study, the use of social distancing in conjunction with mask-wearing and vaccination control strategies was able to achieve optimal control rather than controlling just one or another.
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Synchronization of a Seven-Term Chaotic 4D System Using a Simplified Fixed-Time Adaptive Integral Nonsingular Terminal Sliding Mode Control and Its Circuit Realization
(2024-01-01)
Wongvanich, Napasool
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Moonmuang, Pitchayanin
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Roongmuanpha, Natchanai
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Tangsrirat, Worapong
This work presents an adaptive gain fixed-time synchronization of a seven-term hyperchaotic 4D system, along with its analog circuitry realizations. To facilitate a simplistic circuit realization of the closed loop system, the control design process initiates with the design of a novel, simplified fixed-time stability lemma that gives a lower convergence time, while being easier to compute. A nonlinear, fixed-time adaptive-gain nonsingular terminal sliding mode controller was then designed to synchronize the hyperchaotic 4D system. Theoretical analyses successfully achieved fixed-time synchronization, and computer simulations verified the achievement of zero-error convergence across all states within 1 second, irrespective of the initial conditions and even in the presence of significant parameter and disturbance changes. Analog circuitry implementations of the adaptive gain fixed-time chaotic synchronization configuration were realized using commercially available components, for instance, LF357 and AD633. The circuit equations were devised to replicate those used in the controller, with the goal of facilitating troubleshooting by ensuring simplicity. Electronics workability was tested using PSPICE simulation program. The results demonstrated that active synchronization was achieved in fixed time with less than 1% error across the states in the presence of disturbances. Finally, the developed fixed-time chaotic synchronization was applied to a secure communication system. The results indicate that the original and recovered messages exhibit a high degree of similarity to each other after a fixed duration of 1 second.
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Robust Practical Fixed-Time Control and Application to DC-DC Buck Converter
(2024-01-01)
Wongvanich, Napasool
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Cholahan, Varin
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Tangsrirat, Worapong
This work presents an adaptive fixed-time speed controller of permanent magnet synchronous motors for a class of second-order nonlinear systems based on practical fixed-time stability, in which a sliding mode surface with a constant exponent coefficient is designed to avoid singularities and achieve a fast convergence rate. This method is easy to implement compared to other sophisticated fixed-time controllers. In addition, the upper bound of control inputs is selected to prevent saturation limitations. Following that, the Lyapunov function expresses the close-loop stability of a practical fixed-time controller. An adaptive disturbance rejection with smooth function is presented to attenuate the total disturbances, chattering, and steady-state error. The tracking error is integrated into a bounded residual region within a specified time. Finally, numerical simulations are given to verify the performance of both controller and disturbance rejection mechanisms.

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