• Title/Summary/Keyword: Linear Stability Theory

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Torque Sensorless Decentralized Position/Force Control for Constrained Reconfigurable Manipulator via Non-fragile H Dynamic Output Feedback

  • Zhou, Fan;Dong, Bo;Li, Yuanchun
    • Journal of Electrical Engineering and Technology
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    • v.13 no.1
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    • pp.418-429
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    • 2018
  • This paper studies the decentralized position/force control problem for constrained reconfigurable manipulator without torque sensing. A novel joint torque estimation scheme that exploits the existing structural elasticity of the manipulator joint with harmonic drive model is applied for each joint module. Based on the estimated joint torque and dynamic output feedback technique, a decentralized position/force control strategy is presented. In order to solve the problem of controller parameter perturbation, the non-fragile robust technique is introduced into the dynamic output feedback controller. Subsequently, the stability of the closed-loop system is proved using the Lyapunov theory and linear matrix inequality (LMI) technique. Finally, two 2-DOF constrained reconfigurable manipulators with different configurations are applied to verify the effectiveness of the proposed control scheme in numerical simulation.

Intervalwise Receding Horizon $H_{\infty}$ Tracking Control for Continuous Linear Periodic Systems (연속 시간 선형 주기 시스템에 대한 주기 예측 구간 $H_{\infty}$ 추적 제어)

  • Kim, Ki-Back;Kwon, Wook-Hyun
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.1140-1142
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    • 1996
  • In this paper, a fixed-horizon $H_{\infty}$ tracking control (HTC) for continuous time-varying systems is proposed in state-feedback case. The solution is obtained via the dynamic game theory. From HTC, an intervalwise receding horizon $H_{\infty}$ tracking control (IHTC) for continuous periodic systems is obtained using the intervalwise strategy. The conditions under which IHTC stabilizes the closed-loop system are proposed. Under proposed stability conditions, it is shown that IHTC guarantees the $H_{\infty}$-norm bound.

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Determination of Reactivity by MO Theory (ⅩⅧ). An Intermolecular Perturbation Study of the Acid-Catalyzed Hydrolysis of Diformamide$^*$

  • Kwun, Oh-Cheun
    • Bulletin of the Korean Chemical Society
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    • v.1 no.3
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    • pp.109-112
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    • 1980
  • Ultraviolet spectrophotometric investigations were carried out on monoalkylbenzene-iodine systems in carbon tetrachloride. The results reveal the formation of one-to-one molecular complexes. On the basis of the equilibrium constants for these complexes of representative monosubstituted benzenes, the following order of increasing stability is obtained: i-propyl- ${\Delta}$H, ${\Delta}$G and ${\Delta}$S for the interaction of a number of monoalkyl substituted benzenes with iodine have been determined. In general, it can be said that as ${\Delta}$H becomes increasingly negative, corresponding decreases in the ${\Delta}$G and the ${\Delta}$S values are observed, and these variations are linear. The thermodynamic constants become increasingly negative with increasing monoalkyl substitution of the aromatic donor nucleus. The complex bond is therefore weak, and its formation is accompanied by relatively small entropy changes. Thus, analysis of these findings is discussed.

System simulation and synchronization for optimal evolutionary design of nonlinear controlled systems

  • Chen, C.Y.J.;Kuo, D.;Hsieh, Chia-Yen;Chen, Tim
    • Smart Structures and Systems
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    • v.26 no.6
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    • pp.797-807
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    • 2020
  • Due to the influence of nonlinearity and time-variation, it is difficult to establish an accurate model of concrete frame structures that adopt active controllers. Fuzzy theory is a relatively appropriate method but susceptible to human subjective experience to decrease the performance. This paper proposes a novel artificial intelligence based EBA (Evolved Bat Algorithm) controller with machine learning matched membership functions in the complex nonlinear system. The proposed affine transformed membership functions are adopted and stabilization and performance criterion of the closed-loop fuzzy systems are obtained through a new parametrized linear matrix inequality which is rearranged by machine learning affine matched membership functions. The trajectory of the closed-loop dithered system and that of the closed-loop fuzzy relaxed system can be made as close as desired. This enables us to get a rigorous prediction of stability of the closed-loop dithered system by establishing that of the closed-loop fuzzy relaxed system.

LDI NN auxiliary modeling and control design for nonlinear systems

  • Chen, Z.Y.;Wang, Ruei-Yuan;Jiang, Rong;Chen, Timothy
    • Smart Structures and Systems
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    • v.29 no.5
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    • pp.693-703
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    • 2022
  • This study investigates an effective approach to stabilize nonlinear systems. To ensure the asymptotic nonlinear stability in nonlinear discrete-time systems, the present study presents controller for an EBA (Evolved Bat Algorithm) NN (fuzzy neural network) in the algorithm. In fuzzy evolved NN modeling, the auxiliary circuit with high frequency LDI (linear differential inclusions) and NN model representation is developed for the nonlinear arbitrary dynamics. An example is utilized to demonstrate the system more robust compared with traditional control systems.

Active Trajectory Tracking Control of AMR using Robust PID Tunning

  • Tae-Seok Jin
    • Journal of the Korean Society of Industry Convergence
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    • v.27 no.4_1
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    • pp.753-758
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    • 2024
  • Trajectory tracking of the AMR robot is one research for the AMR robot navigation. For the control system of the Autonomous mobile robot(AMR) being in non-honolomic system and the complex relations among the control parameters, it is d ifficult to solve the problem based on traditional mathematics model. In this paper, we presents a simple and effective way of implementing an adaptive tracking controller based on the PID for AMR robot trajectory tracking. The method uses a non-linear model of AMR robot kinematics and thus allows an accurate prediction of the future trajectories. The proposed controller has a parallel structure that consists of PID controller with a fixed gain. The control law is constructed on the basis of Lyapunov stability theory. Computer simulation for a differentially driven non-holonomic AMR robot is carried out in the velocity and orientation tracking control of the non-holonomic AMR. The simulation results of wheel type AMR robot platform show that the proposed controller is more robust than the conventional back-stepping controller to show the effectiveness of the proposed algorithm.

Control of Nonlinear Crane Systems with Perturbation using Model Matching Approach (모델매칭 기법을 이용한 시스템 섭동을 갖는 비선형 크레인시스템 제어)

  • Cho, Hyun-Cheol;Lee, Jin-Woo;Lee, Young-Jin;Lee, Kwon-Soon
    • Journal of Navigation and Port Research
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    • v.31 no.6
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    • pp.523-530
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    • 2007
  • Crane systems are very important in industrial fields to carry heavy objects such that many investigations about control of the systems are actively conducted for enhancing its control performance. This paper presents an adaptive control approach using the model matching for a complex 3-DOF nonlinear crane system. First, the system model is linearized through feedback linearization method and then PD control is applied in the approximated model. This linear model is considered as nominal to derive corrective control law for a perturbed crane model using Lyapunov theory. This corrective control is primitively aimed to compensate real-time control deviation due to partially known perturbation. We additionally study stability analysis of the crane control system using Lyapunov perturbation theory. Evaluation of our control approach is numerically carried out through computer simulation and its superiority is demonstrated comparing with the classical control.

Robust Control Design for a Two-Wheeled Inverted Pendulum Mobile Robot (이륜 도립진자 이동로봇을 위한 강인제어기 설계)

  • Yoo, Dong Sang
    • Journal of the Korean Institute of Intelligent Systems
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    • v.26 no.1
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    • pp.16-22
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    • 2016
  • The research on two-wheeled inverted pendulum (TWIP) mobile robots has been ongoing in a number of robotic laboratories around the world. In this paper, we consider a robust controller design for the TWIP mobile robot driving on uniform slopes. We use a 2 degree-of-freedom (DOF) model which is obtained by restricting the spinning motion in a 3 DOF motion dynamic equation. In order to design the robust controller guaranteeing stability of the TWIP mobile robot driving on inclined surface, we propose a sliding mode control based on the theory of variable structure systems and design a sliding surface using the theory of the linear quadratic regulation (LQR). For simulation, the dynamic model of the TWIP mobile robot is constructed using Mathworks' Simulink and the sliding mode control is also implemented using Simulink. From simulation results, we show that the proposed controller effectively controls the TWIP mobile robot driving on slopes.

Theoretical buckling analysis of inhomogeneous plates under various thermal gradients and boundary conditions

  • Laid Lekouara;Belgacem Mamen;Abdelhakim Bouhadra;Abderahmane Menasria;Kouider Halim Benrahou;Abdelouahed Tounsi;Mohammed A. Al-Osta
    • Structural Engineering and Mechanics
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    • v.86 no.4
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    • pp.443-459
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    • 2023
  • This study investigates the theoretical thermal buckling analyses of thick porous rectangular functionally graded (FG) plates with different geometrical boundary conditions resting on a Winkler-Pasternak elastic foundation using a new higher-order shear deformation theory (HSDT). This new theory has only four unknowns and involves indeterminate integral variables in which no shear correction factor is required. The variation of material properties across the plate's thickness is considered continuous and varied following a simple power law as a function of volume fractions of the constituents. The effect of porosity with two different types of distribution is also included. The current formulation considers the Von Karman nonlinearity, and the stability equations are developed using the virtual works principle. The thermal gradients are involved and assumed to change across the FG plate's thickness according to nonlinear, linear, and uniform distributions. The accuracy of the newly proposed theory has been validated by comparing the present results with the results obtained from the previously published theories. The effects of porosity, boundary conditions, foundation parameters, power index, plate aspect ratio, and side-to-thickness ratio on the critical buckling temperature are studied and discussed in detail.

Proposal of Sliding Stability Assessment Formulas for an Interlocking Caisson Breakwater under Wave Forces (파랑하중에 대한 인터로킹 케이슨 방파제의 미끌림 안정성 평가식 제안)

  • Park, Woo-Sun;Won, Deokhee;Seo, Jihye
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.2
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    • pp.77-82
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    • 2017
  • Recently, the possibility of abnormal waves of which height is greater than design wave height have been increased due to the climate change, and therefore it has been urgent to secure the stability for harbor structures. As a countermeasure for improving the stability of conventional caisson breakwaters, a method has been proposed in which adjacent caissons are interlocked with each other to consecutively resist the abnormal wave forces. In order to reflect this research trend, the reduction effect of the maximum wave force resulted from introducing a long caisson has been presented in the revision to the design criteria for ports and fishing harbors and commentary. However, no method has been proposed to evaluate the stability of interlocking caisson breakwater. In this study, we consider the effect of the phase difference of the oblique incidence of the wave based on the linear wave theory and apply the Goda pressure formula for considering design wave pressure distribution in the vertical direction. Sliding stability assessment formula of an interlocking caisson breakwater is proposed for regular, irregular, and multi-directional irregular wave conditions.