Publications

A discontinuous control law is proposed to achieve global asymptotic stabilization for oscillators with bounded delayed input. Only the “position” signal is used to generate the piecewise constant control signal. The asymptotic stability is analyzed by Poincare Map method and conditions are proposed. The effectiveness of this control law is verified by simulation studies.

The design and self-assembly of novel rhomboidal metallodendrimers via coordination-driven self-assembly is described. By employing newly designed 60° ditopic donor linkers substituted with Fréchet-type dendrons and appropriate 120° rigid di-Pt(II) acceptor subunits, a variety of [G-1]-[G-3] rhomboidal metallodendrimers with well-defined shape and size were prepared under mild conditions in high yields. The supramolecular metallodendrimers were characterized with multinuclear NMR ((1)H and (31)P), mass spectrometry (CSI-TOF-MS), and elemental analysis. Isotopically resolved mass spectrometry data support the existence of the metallodendrimers with rhomboidal cavities, and NMR data were consistent with the formation of all ensembles. The shape and size of all rhomboidal metallodendrimers were investigated with the PM6 semiempirical molecular orbital method.

This article is concerned with both consensus and coordinated path-following control for multiple nonholonomic wheeled mobile robots. In the design, the path-following control is decoupled into the longitudinal control (speed control) and the lateral control (heading control) for the convenience of implementation. Different from coordinated trajectory tracking control schemes, the proposed control scheme removes the temporal constraint, which greatly improves the coordination robustness. In particular, two new coordinated error variables describing a chasing-and-waiting strategy are introduced in the proposed coordinated path-following control for injective paths and circular paths, respectively. All the closed-loop signals have proved to be asymptotically stable in the Lyapunov sense. Finally, simulation results under three typical paths are presented to verify the proposed coordination controllers.

This article addresses neurodynamics-based model predictive control of continuous-time under-actuated mechatronic systems. The control problem is formulated as a global optimization problem based on sampled data, which is solved by using a collaborative neurodynamic approach. The closed-loop system is proven to be asymptotically stable. Specific applications on control of autonomous surface vehicles and unmanned wheeled vehicles are elaborated to substantiate the efficacy of the approach.

This paper is concerned with the design problem of robust H∞ control for linear networked control systems (NCSs) with network-induced delay and data packet dropout. By choosing a new Lyapunov-Krasovskii functional, a sufficient condition on the existence of robust H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> controller is derived in the form of a matrix inequality. No model transformation is needed and no redundant matrix variable is introduced. Then an iterative algorithm is introduced for obtaining the robust H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> controller design method based on the matrix inequality. No parameter needs to be selected in advance. Two numerical examples are finally given to illustrate the effectiveness of the proposed algorithm.

This paper is concerned with H∞ control of a networked control system (NCS). First, the NCS is modelled as a linear system with an interval time–varying delay. Second, a delay decomposition approach is developed to derive a less conservative bounded real lemma (BRL). Based on this BRL, delay-dependent conditions for the existence of a state feedback controller, which ensures internally asymptotic stability and a prescribed H∞ performance level of the closedloop system, are derived in terms of a nonlinear matrix inequality. Third, the nonconvex feasibility problem is converted into a nonlinear minimization problem subject to a set of linear matrix inequalities (LMIs), from which the suitable controller can be designed by an iterative algorithm. Finally, two numerical examples are given to show the effectiveness of the obtained results.

This paper is concerned with finite-time containment control problem for second-order nonlinear multi-agent systems with multiple dynamic leaders. Two new containment control protocols are developed to ensure that all followers converge to the dynamic convex hull spanned by the dynamic leaders in a finite time based on the terminal sliding mode and non-singular terminal sliding model, respectively. Moreover, the non-singular terminal sliding mode method is used to eliminate the singular problem associated with the terminal sliding mode control. Criteria on the existence of desired containment control protocols are also derived. Furthermore, the settling time is estimated under the proposed protocols. Simulation results illustrate the effectiveness of the developed theory in the last.

This paper is concerned with the stability of networked control systems in the discrete-time domain. A new bounding technique is proposed to estimate some finite-sum terms appearing in the forward difference of the chosen Lyapunov functional. This new bounding technique can provide tighter upper bounds for some finite-sum terms and avoid overly bounding for the finite-sum terms. Then a novel delay-dependent stability criterion is derived by using this new bounding technique. Compared with some existing stability criteria in the published literature, the novel stability criterion is proven theoretically to be less conservative and is shown to be of smaller numerical complexity.

This paper is concerned with the problem of robust H ∞ controller design for a class of uncertain networked control systems (NCSs). The network‐induced delay is of an interval‐like time‐varying type integer, which means that both lower and upper bounds for such a kind of delay are available. The parameter uncertainties are assumed to be normbounded and possibly time‐varying. Based on Lyapunov‐Krasovskii functional approach, a robust H ∞ controller for uncertain NCSs is designed by using a sum inequality which is first introduced and plays an important role in deriving the controller. A delay‐dependent condition for the existence of a state feedback controller, which ensures internal asymptotic stability and a prescribed H ∞ performance level of the closed‐loop system for all admissible uncertainties, is proposed in terms of a nonlinear matrix inequality which can be solved by a linearization algorithm, and no parameters need to be adjusted. A numerical example about a balancing problem of an inverted pendulum on a cart is given to show the effectiveness of the proposed design method.

This paper investigates challenging fully unsupervised defogging problems, i.e., how to remove fog by feeding only foggy images in deep neural networks rat

This paper is concerned with order-preserved preset-time cooperative control of multi-agent systems with directed graphs. A novel monotone system-based approach is proposed to preserve the initial order of agents while guaranteeing the preset-time state agreement. Specifically, three different distributed controllers together with sufficient conditions are designed to realize leaderless consensus, leader-following consensus, and containment control, respectively. The proposed controllers facilitate preset-time deployment of agents in practical scenarios with collision avoidance requirement. Comparison studies through a numerical example are carried out to illustrate the effectiveness of the proposed controllers.

In this paper, we prove the existence of an isometric embedding near the origin in R3 of a two-dimensional metric with nonpositive Gaussian curvature. The Gaussian curvature can be allowed to be highly degenerate near the origin. Through the Gauss-Codazzi equations, the embedding problem is reduced to a 2 × 2 system of the first order derivaties and is solved via the method of Nash-Moser-Hörmander iterative scheme.

An event-triggered mechanism is of great efficiency in reducing unnecessary sensor samplings/transmissions and, thus, resource consumption such as sensor power and network bandwidth, which makes distributed event-triggered estimation a promising resource-aware solution for sensor network-based monitoring systems. This paper provides a survey of recent advances in distributed event-triggered estimation for dynamical systems operating over resource-constrained sensor networks. Local estimates of an unavailable state signal are calculated in a distributed and collaborative fashion based on only invoked sensor data. First, several fundamental issues associated with the design of distributed estimators are discussed in detail, such as estimator structures, communication constraints, and design methods. Second, an emphasis is laid on recent developments of distributed event-triggered estimation that has received considerable attention in the past few years. Then, the principle of an event-triggered mechanism is outlined and recent results in this subject are sorted out in accordance with different event-triggering conditions. Third, applications of distributed event-triggered estimation in practical sensor network-based monitoring systems including distributed grid-connected generation systems and target tracking systems are provided. Finally, several challenging issues worthy of further research are envisioned.

This paper addresses the networked $$H_\infty $$ control problem for active suspension systems equipped with dynamic dampers. First, a networked active suspension...