المؤلفون: Xu, Yuanhong¹ (AUTHOR) s199728y@st.go.tuat.ac.jp, Deng, Mingcong¹ (AUTHOR) deng@cc.tuat.ac.jp

المصدر: Axioms (2075-1680). Feb2024, Vol. 13 Issue 2, p116. 16p.

مصطلحات موضوعية: *CLOSED loop system stability, *FACTORIZATION

مستخلص: In this paper, the robustness of a system with sundry disturbed open loop dynamics is investigated by employing robust right coprime factorization (RRCF). These sundry disturbed open loop dynamics are present not only in the feed forward path, but also within the feedback loop. In such a control framework, the nominal plant is firstly right coprime factorized and a feed forward and a feedback controllers are designed based on Bezout identity to ensure the overall stability. Subsequently, considering the sundry disturbed open loop dynamics, a new condition formulated as a disturbed Bezout identity is put forward to achieve the closed loop stability of the system, even in the presence of disturbances existing in sundry open loops, where in the feedback loop a disturbed identity operator is defined. This approach guarantees the system robustness if a specific inequality condition is satisfied. And, it should be noted that the proposed approach is applicable to both linear and nonlinear systems with sundry disturbed open loop dynamics. Simulations demonstrate the effectiveness of our methodology. [ABSTRACT FROM AUTHOR]

المؤلفون: Wang, Shihao¹ (AUTHOR), Zheng, Shiqi¹ (AUTHOR) zhengshiqi@cug.edu.cn, Deng, Yushu² (AUTHOR) zhengshiqi@cug.edu.cn, Jiang, Zhouxiang³ (AUTHOR), Song, Bao⁴ (AUTHOR), Tang, Xiaoqi⁴ (AUTHOR)

المصدر: Entropy. Oct2022, Vol. 24 Issue 10, p1360-N.PAG. 15p.

مصطلحات موضوعية: *MANIPULATORS (Machinery), *CLOSED loop system stability, *ADAPTIVE control systems, *ROBOT control systems, *NONLINEAR systems, *EXPONENTIAL stability

مستخلص: This paper concentrates on the study of logic-based switching adaptive control. Two different cases will be considered. In the first case, the finite time stabilization problem for a class of nonlinear system is studied. Based on the recently developed adding a barrier power integrator technique, a new logic-based switching adaptive control method is proposed. In contrast with the existing results, finite time stability can be achieved when the considered systems contain both fully unknown nonlinearties and unknown control direction. Moreover, the proposed controller has a very simple structure and no approximation methods, e.g., neural networks/fuzzy logic, are needed. In the second case, the sampled-data control for a class of nonlinear system is investigated. New sampled-data logic-based switching mechanism is proposed. Compared with previous works, the considered nonlinear system has an uncertain linear growth rate. The control parameters and the sampling time can be adjusted adaptively to render the exponential stability of the closed loop system. Applications in robot manipulators are conducted to verify the proposed results. [ABSTRACT FROM AUTHOR]

المؤلفون: Maaruf, Muhammad, Hamanah, Waleed M., Abido, Mohammad A.

المصدر: Mathematics (2227-7390); Feb2023, Vol. 11 Issue 4, p991, 19p

مصطلحات موضوعية: BACKSTEPPING control method, RADIAL basis functions, CLOSED loop system stability, SLIDING mode control, ADAPTIVE control systems, EULER angles

مستخلص: This article presents a hybrid backstepping consisting of two robust controllers utilizing the approximation property of a radial basis function neural network (RBFNN) for a quadrotor with time-varying uncertainties. The quadrotor dynamic system is decoupled into two subsystems: the position and the attitude subsystems. As part of the position subsystem, adaptive RBFNN backstepping control (ANNBC) is developed to eliminate the effects of uncertainties, trace the quadrotor's position, and provide the desired roll and pitch angles commands for the attitude subsystem. Then, adaptive RBFNN backstepping is integrated with integral fast terminal sliding mode control (ANNBIFTSMC) to track the required Euler angles and improve robustness against external disturbances. The proposed technique is advantageous because the quadrotor states trace the reference states in a short period of time without requiring knowledge of dynamic uncertainties and external disturbances. In addition, because the controller gains are based on the desired trajectories, adaptive algorithms are used to update them online. The stability of a closed loop system is proved by Lyapunov theory. Numerical simulations show acceptable attitude and position tracking performances. [ABSTRACT FROM AUTHOR]

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المؤلفون: Medrano-Hermosillo, Jesús Alfonso, Lozoya-Ponce, Ricardo, Rodriguez-Mata, Abraham Efraím, Baray-Arana, Rogelio

المصدر: Mathematics (2227-7390); Feb2023, Vol. 11 Issue 3, p572, 17p

مصطلحات موضوعية: THEORY of screws, HAMILTON'S equations, CLOSED loop system stability, ROBOT control systems, SLIDING mode control, MANIPULATORS (Machinery), SCREWS

مستخلص: The following paper talks about the dynamic modeling and control of robot manipulators using Hamilton's equations in the screw theory framework. The difference between the proposed work with diverse methods in the literature is the ease of obtaining the laws of control directly with screws and co-screws, which is considered modern robotics by diverse authors. In addition, geometric algebra (GA) is introduced as a simple and iterative tool to obtain screws and co-screws. On the other hand, such as the controllers, the Hamiltonian equations of motion (in the phase space) are developed using co-screws and screws, which is a novel approach to compute the dynamic equations for robots. Regarding the controllers, two laws of control are designed to ensure the error's convergence to zero. The controllers are computed using the traditional feedback linearization and the sliding mode control theory. The first one is easy to program and the second theory provides robustness for matched disturbances. On the other hand, to prove the stability of the closed loop system, different Lyapunov functions are computed with co-screws and screws to guarantee its convergence to zero. Finally, diverse simulations are illustrated to show a comparison of the designed controllers with the most famous approaches. [ABSTRACT FROM AUTHOR]

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المؤلفون: Ivanescu, Mircea, Dumitrache, Ioan, Popescu, Nirvana, Popescu, Decebal

المصدر: Fractal & Fractional; Jan2023, Vol. 7 Issue 1, p23, 18p

مصطلحات موضوعية: ELECTRIC wheelchairs, PARKINSON'S disease, CLOSED loop systems, CLOSED loop system stability, PREVENTIVE medicine, DEEP brain stimulation

مستخلص: The paper focuses on the design of an intelligent interface that compensates for the incapacity of a person with Parkinson's disease to drive a wheelchair. The fractional order model that defines a person with Parkinson's disease is investigated. An identification technique based on the analysis of the frequency behavior of the movement of a wheelchair driven by a with Parkinson's disease person on the test trajectory is proposed and a delay time crossover model with fractional order exponent β = 1.5 is inferred. The fractional dynamic model of the "disabled man-wheelchair" system is discussed and a control system is proposed to compensate for the inability of the wheelchair driver. The conditions that ensure the stability of the closed loop control system are inferred. An experimental technique for analyzing movement performance is developed and a quality index is proposed to evaluate these experiments. The values of this index on the tests performed on Parkinson's patients are analyzed and discussed. [ABSTRACT FROM AUTHOR]

: Copyright of Fractal & Fractional is the property of MDPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Nguyen, Manh Hung, Ahn, Kyoung Kwan

المصدر: Applied Sciences (2076-3417); Nov2022, Vol. 12 Issue 22, p11501, 17p

مصطلحات موضوعية: CLOSED loop system stability, VOLTAGE, CASCADE control

مستخلص: This paper aims to provide a novel control framework for exactly regulating the output voltage of floating interleaved boost converters (FIBCs), which have been widely employed in fuel cell applications in recent years. Firstly, a mathematical model of the FIBC is constructed according to Kirchhoff's current and voltage loop principles. Then a cascade control structure with a current inner loop and voltage outer loop is developed to achieve the desired voltage regulation performance. The current controller is established based on the generalized super-twisting algorithm (GSTA) to ensure that the inductor current exactly follows the current reference, which is generated by the outer loop. Meanwhile, an active disturbance rejection control (ADRC) framework is utilized for robustly regulating the output voltage despite the presence of input variation and load change in the voltage control loop based on a nonlinear continuous GSTA-based extended state observer (GSTA-based ESO). The stability of a closed loop system based on the GSTA controller and the GSTA-based ESO is conclusively proven using the Lyapunov theory. The Simscape model of the FIBC is developed, which is used to verify the feasibility and the appropriateness of the recommended control algorithm. Finally, numerical simulations are carried out to demonstrate the effectiveness of the proposed method compared to several previous works. [ABSTRACT FROM AUTHOR]

: Copyright of Applied Sciences (2076-3417) is the property of MDPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Versaci, Mario

المصدر: Mathematics (2227-7390); Nov2022, Vol. 10 Issue 21, p3965, 5p

مصطلحات موضوعية: ELECTRICAL engineering, NEWSVENDOR model, ADVECTION-diffusion equations, INDUSTRIAL engineering, ENGINEERING models, MATHEMATICAL models, CLOSED loop system stability, NUMERICAL solutions to differential equations

مستخلص: A. Montisci, S. Cargangiu, G. Sias, B. Cannas and A. Fanni, in [[16]], present a real time bolometer tomographic reconstruction algorithm in nuclear fusion reactors based on the combination of highly correlated grid elements to yield a square coefficient matrix with sufficiently low condition number. The procedure was derived from the polynomial reproduction properties satisfied by the Hermite splines without requiring the explicit construction/evaluation of the basic functions. The paper authored by Y.E. Shao and S.C. Lin [[1]] presents an innovative time-delay neural network-based classifier to diagnose the quality variables that cause out-of-control signals for a normal multivariate process with variance shifts. It is now clear that cooperation between academia and industries is crucial for social, cultural, technological and economic progress and innovation. [Extracted from the article]

: Copyright of Mathematics (2227-7390) is the property of MDPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Vivert, Miguel, Diez, Rafael, Cousineau, Marc, BERNAL COBALEDA, Diego, Patino, Diego, Ladoux, Philippe

المساهمون: LADOUX, Philippe/0000-0002-2697-8707

مصطلحات موضوعية: multilevel inverter, selective harmonic elimination, polynomial transform, newton-raphson method, closed-loop system

الوصف: Selective Harmonics Elimination is a high-efficiency modulation method for multilevel inverters that allows handling very high voltage applications. It eliminates the most significant harmonics and fixes the desired fundamental component. The main issue of these techniques is the complex process to obtain the appropriate switching-angles, being necessary to calculate them offline, meaning that if some disturbances occur, the system will not be compensated. This article proposes a real-time selective harmonic elimination for a single-phase cascaded multilevel inverter. The control strategy maintains constant the fundamental component of the output voltage while removing its third, fifth, and seventh order harmonics. The switching-angles are dynamically adapted to compensate for variations in the input voltage and the load. This is done by obtaining a virtual dynamic system using Groebner basis, an adaptation of the Newton-Raphson method, and implementing a digital PI controller into the virtual dynamical model. This adaptive modulation technique is validated experimentally in a 200 W, 9-levels Cascaded Full Bridge Inverter, canceling the harmonics and regulating the fundamental components in all the tests. The developed theory can be adapted or extended for any multilevel inverter modulated by selective harmonic elimination. ; The authors would like to thank the “Secretaría de Educación Superior, Ciencia, Tecnología e Innovación” of the Ecuadorian Government (SENESCYT) that supported this study with the contract no: 8859.

وصف الملف: application/pdf

العلاقة: Energies, 15 (9) (Art N° 2995); http://hdl.handle.net/1942/37498Test; 15; WOS:000794588100001

الإتاحة: https://doi.org/10.3390/en15092995Test
http://hdl.handle.net/1942/37498Test

المؤلفون: Kim, Wonhee¹ (AUTHOR) whkim79@cau.ac.kr, Suh, Sangmin² (AUTHOR) sangminsuh@gwnu.ac.kr

المصدر: Mathematics (2227-7390). Sep2020, Vol. 8 Issue 9, p1434. 1p.

مصطلحات موضوعية: *CLOSED loop system stability, *LINEAR matrix inequalities

مستخلص: For several decades, disturbance observers (DOs) have been widely utilized to enhance tracking performance by reducing external disturbances in different industrial applications. However, although a DO is a verified control structure, a conventional DO does not guarantee stability. This paper proposes a stability-guaranteed design method, while maintaining the DO structure. The proposed design method uses a linear matrix inequality (LMI)-based H ∞ control because the LMI-based control guarantees the stability of closed loop systems. However, applying the DO design to the LMI framework is not trivial because there are two control targets, whereas the standard LMI stabilizes a single control target. In this study, the problem is first resolved by building a single fictitious model because the two models are serial and can be considered as a single model from the Q-filter point of view. Using the proposed design framework, all-stabilizing Q filters are calculated. In addition, for the stability and robustness of the DO, two metrics are proposed to quantify the stability and robustness and combined into a single unified index to satisfy both metrics. Based on an application example, it is verified that the proposed method is effective, with a performance improvement of 10.8 % . [ABSTRACT FROM AUTHOR]

المؤلفون: Grčar, Bojan¹ (AUTHOR) bojan.grcar@um.si, Hofer, Anton² (AUTHOR) anton.hofer@tugraz.at, Štumberger, Gorazd¹ (AUTHOR)

المصدر: Energies (19961073). Jan2020, Vol. 13 Issue 1, p175-175. 1p. 1 Diagram, 1 Chart, 8 Graphs.

مصطلحات موضوعية: *TORQUE control, *CLOSED loop system stability, *NONLINEAR analysis

مستخلص: In this paper, a method for induction machine (IM) torque/speed tracking control derived from the 3-D non-holonomic integrator including drift terms is proposed. The proposition builds on a previous result derived in the form of a single loop non-linear state controller providing implicit rotor flux linkage vector tracking. This concept was appropriate only for piecewise constant references and assured minimal norm of the stator current vector during steady-states. The extended proposition introduces a second control loop for the rotor flux linkage vector magnitude that can be either constant, programmed, or optimized to achieve either maximum torque per amp ratio or high dynamic response. It should be emphasized that the same structure of the controller can be used either for torque control or for speed control. Additionally, it turns out that the proposed controller can be easily adapted to meet different objectives posed on the drive system. The introduced control concept assures stability of the closed loop system and significantly improves tracking performance for bounded but arbitrary torque/speed references. Moreover, the singularity problem near zero rotor flux linkage vector length is easily avoided. The presented analyses include nonlinear effects due to magnetic saturation. The overall IM control scheme includes cascaded high-gain current controllers based on measured electrical and mechanical quantities together with a rotor flux linkage vector estimator. Simulation and experimental results illustrate the main characteristics of the proposed control. [ABSTRACT FROM AUTHOR]