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Your search keyword '"Lee, Ti-Chung"' showing total 26 results
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26 results on '"Lee, Ti-Chung"'

2. Signal Sets on Time Scales with Application to Hybrid Systems

Author

Lee, Ti-Chung, Tan, Ying, and Mareels, Iven

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

Recently, time scales calculus is developed to unify continuous and discrete analysis. By extending the definition of time scales properly, this paper introduces the concept of a signal set as well as its stability properties in terms of the so-called pseudo distance measure. This leads to more general Lyapunov like conditions to check stability properties of systems with hybrid nature. By way of examples, the proposed framework is used to model hybrid systems with simplicity and flexibility to characterize trajectories in the behavior of hybrid systems., Comment: 8 pages, Just submitted to IEEE TAC

Published
2020

3. Invariance Principles and Observability in Switched Systems with an Application in Consensus

Author

Lee, Ti-Chung, Tan, Ying, Su, Youfeng, and Mareels, Iven

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

Using any nonnegative function with a nonpositive derivative along trajectories to define a virtual output, the classic LaSalle invariance principle can be extended to switched nonlinear time-varying (NLTV) systems, by considering the weak observability (WO) associated with this output. WO is what the output informs about the limiting behavior of state trajectories (hidden in the zero locus of the output). In the context of switched NLTV systems, WO can be explored using the recently established framework of limiting zeroing-output solutions. Adding to this, an extension of the integral invariance principle for switched NLTV systems with a new method to guarantee uniform global attractivity of a closed set (without assuming uniform Lyapunov stability or dwell-time conditions) is proposed. By way of illustrating the proposed method, a leaderless consensus problem for nonholonomic mobile robots with a switching communication topology is addressed, yielding a new control strategy and a new convergence result.

Published
2020

8. Agreements of Nonlinear Opinion Dynamics in Switching Social Networks

Author

Lee, Ti-Chung and Su, Youfeng

Abstract

This article formulates and analyzes agreements of the nonlinear opinion dynamics in social networks according to switching interactions, where the agents' susceptibilities depend on current states. These switching interactions are formulated by switching directed graphs with some mild joint connectivity, and depicted by nonlinear switching model. An extended LaSalle invariance principle is established for analyzing the agreements of this switching model as well as three specialized scenarios, where the limiting equations formed by the weak* convergence are used to study the steady-state behavior so that the stability analysis is substantially simplified in the sense that the “$\max - \min$” Lyapunov function may be assumed to be constant along any bounded forward complete solutions of limiting equations. Examples and simulations are used to verify the obtained results.

Published
2024
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18. Practical Regulation of Nonholonomic Systems Using Virtual Trajectories and LaSalle Invariance Principle.

Author

Zhang, Dianfeng, Lee, Ti-Chung, Sun, Xi-Ming, and Wu, Yuhu

Subjects
*NONHOLONOMIC dynamical systems, *SPHERES, *PROBLEM solving, *NONLINEAR systems
Abstract

This paper investigates the regulation problem for a class of nonholonomic systems that includes power form systems and an approximated system of the rolling sphere as special cases. The basic idea is first to introduce a virtual periodic moving trajectory that satisfies certain persistent excitation condition (PE) and has the zero value at some time instants. Based on LaSalle invariance principle, the associated tracking problem is then solved under a necessary condition for stabilization and particularly true for the power form systems and the rolling sphere. With the help of virtual trajectory, the achieved tracking result is applied to the regulation problem and used to guarantee practical stability. The proposed controllers have a simple and explicit form, and hence are easily implemented. Simultaneously, fast convergence is guaranteed, thanks to the $\boldsymbol {\mathcal {K}}$ -exponential convergence. More interestingly, the used approach is adding sufficiently exciting signals to the systems by considering virtual tracking signals so that the attractivity of the origin can be guaranteed based on LaSalle invariance principle. Thus, it is possible to extend the proposed results to more general systems. To verify the effectiveness of the proposed scheme, interesting simulation results are presented. [ABSTRACT FROM AUTHOR]

Published
2020
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23. Detectability and Uniform Global Asymptotic Stability in Switched Nonlinear Time-Varying Systems.

Author

Lee, Ti-Chung, Tan, Ying, and Mareels, Iven

Subjects
*TIME-varying systems, *NONLINEAR systems, *GLOBAL asymptotic stability, *DEFINITIONS
Abstract

This paper employs detectability ideas to decide uniform global asymptotic stability (UGAS) of the trivial solution for a class of switched nonlinear time-varying systems when the trivial solution is uniformly globally stable. Using the notion of limiting behaviors of the state, output, and switching signals, the concept of a limiting zeroing-output solution is introduced. This leads to a definition of weak zero-state detectability (WZSD) that can be used to check UGAS, (uniformly for a set of switched signals). En route to establish this, a number of new stability results are derived. For example, under appropriate conditions, it is feasible to decide UGAS even when the switching signal does not satisfy an averaged dwell-time condition. It is also shown that WZSD of the original switched system can be verified by detectability conditions of much simpler auxiliary systems. Moreover, UGAS can be guaranteed without requiring that in each allowable system (without switching), the trivial solution is attractive. The effectiveness of the proposed concept is illustrated by a few examples including a switched semi-quasi-Z-source inverter. [ABSTRACT FROM AUTHOR]

Published
2020
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