910 publications from this institution
The robust stability problem of uncertain linear time-delay systems is investigated using a refined discretized Lyapunov functional approach. The uncertainty under consideration is norm-bounded, and possibly time-varying. A new stability criterion is derived. The computational requirement is reduced for the same discretization mesh. Examples show that the results obtained by this new criterion significantly improve the estimate of the stability limit over some existing results in the literature.
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This study is concerned with the event-triggered control for networked control systems via dynamic output feedback controllers (DOFCs). The output measurement signals of the physical plant are sampled periodically. An output-based discrete event-triggering mechanism is introduced to choose those only necessary sampled-data packets to be transmitted through a communication network for controller design. Under this event-triggering mechanism, the resultant closed-loop system is first modelled as a linear system with an interval time-varying delay. Then a novel stability criterion is established by employing the Lyapunov–Krasovskii functional approach. Based on this stability criterion, a new sufficient condition is derived to co-design both the desired DOFCs and the event-triggering parameters. Finally, a satellite control system is taken to show the effectiveness of the proposed method.
A series of new dendritic platinum bisferrocenylacetylide complexes have been synthesized utilizing the coupling reaction of trans-Pt complexes with C–H bonds in alkynes as key steps. These new bimetallic dendrimers were fully characterized by multinuclear NMR ( 1 H, 13 C, and 31 P) and mass spectrometry (MALDI-TOF-MS and CSI-TOF-MS). Electrochemical studies of these complexes were carried out and revealed that all of the redox moieties are stable, independent, and electrochemically active. In addition, all metallodendrimers show one-electron reaction responses, and the increased sizes of these complexes did not exhibit a dramatic influence on the diffusion coefficient.
This paper is concerned with cyber-physical attack detection problem in networked control systems subject to limited communication bandwidth. This constraint arises when an attack detection system is located at a remote site and so the required signals, measurement output and control signals, need to be transmitted over a digital communication channel. Therefore, data before being sent to the remote site must be encoded and converted from analog signals to digital signals by using quantizer. A quantizer maps the amount of information from a continuous space to a finite set which is compatible with the limited communication bandwidth. Considering the quantized measurement output, a detection algorithm by means of a set-membership filtering approach will be proposed. The algorithm consists of a prediction ellipsoid set and an estimation ellipsoid set updated with the quantized measurement output. The detection method depends on the existence of intersection between two sets computed by the filter. Simulation results for some possible physical and cyber attacks are provided to demonstrate the effectiveness of the proposed method.
The problem of H∞ filter design for linear systems with interval time-varying delay is investigated. The interval time-varying delay is considered as two cases: continuous and differentiable with the bounded derivative of the time-varying delay. Neither model transformation nor bounding techniques for cross terms is employed. A delay-dependent sufficient condition on the existence of an H∞ filter is derived in the form of non-convex matrix inequalities by introducing a new Lyapunov–Krasovskii functional which is based on both left and right endpoints of the time-varying delay interval. In order to find a feasible solution to the non-convex matrix inequalities, a minimisation problem is formulated and the problem can be solved by using a cone complementarity. Finally, two examples are given to illustrate the effectiveness of the proposed method.
This chapter is concerned with distributed energy management and control issues of both generators and loads, aiming to maximize the total social welfare which balances generation-side expanses, user-side payments, and transmission line costs. A distributed control...
An integrated vehicle dynamics control (IVDC) algorithm, developed for improving vehicle handling and stability under critical lateral motions, is discussed in this paper. The IVDC system utilises integral and nonsingular fast terminal sliding mode (NFTSM) control strategies and coordinates active front steering (AFS) and direct yaw moment control (DYC) systems. When the vehicle is in the normal driving situation, the AFS system provides handling enhancement. If the vehicle reaches its handling limit, both AFS and DYC are then integrated to ensure the vehicle stability. The major contribution of this paper is in improving the transient response of the vehicle yaw rate and sideslip angle tracking controllers by implementing advanced types of sliding mode strategies, namely integral terminal sliding mode and NFTSM, in the IVDC system. Simulation results demonstrate that the developed control algorithm for the IVDC system not only has strong robustness against uncertainties but also improves the transient response of the control system.
The free-weighting-matrix approach is developed to study the H ∞ control of linear discrete-time systems with an interval-like time-varying delay. First, a delay- and range-dependent criterion for a given H ∞ performance is derived. Second, a memoryless H ∞ state-feedback controller is designed based on a performance analysis. Finally, two numerical examples demonstrate the effectiveness of the proposed method and show that both the upper bound and range of an interval-like time-varying delay affect the stability and/or H ∞ performance of a system. Keywords: Discrete-time systemsTime-varying delayStabilising H ∞ controlLinear matrix inequality (LMI) Acknowledgements This research work was supported in part by the National Science Foundation of China under Grant Nos. 60425310 and 60574014, the Program for New Century Excellent Talents in University, the Doctor Subject Foundation of China under Grant No. 20050533015; and the Hunan Provincial Natural Science Foundation of China. The research work of Qing-Long Han was supported in part by Central Queensland University for the Research Advancement Awards Scheme Project 'Robust Fault Detection, Filtering and Control for Uncertain Systems with Time-Varying Delay' (January 2006 to December 2008).
In this chapter, we first introduce some underlying concepts of cooperative control. Then, we briefly review how fixed-time cooperative control is motivated and promoted in the control community. Moreover, we present some related work of distributed optimization and...
This paper is concerned with distributed cooperative longitudinal platooning control of connected automated vehicles over resource-constrained vehicular ad-hoc networks. First, a general platoon-based control framework is constructed, which simultaneously accounts for unknown leader control input, external disturbances, intermittent data samplings and transmissions, various spacing policies, and different vehicle-to-vehicle communication topologies. To alleviate excessive occupancy of the limited communication resources, an adaptive Zeno-free event-triggered communication mechanism is developed to determine when the sampling and transmission actions of vehicular data should be performed among interacting vehicles. Then, a scalable co-design approach for the desired adaptive platoon controller as well as event triggering condition is developed. One promising feature of the proposed platooning control strategy is that it is independent on the platoon scale or any global knowledge of the associated communication topology, and thus implementable on each vehicle in a scalable manner. Finally, several numerical case studies are conducted to verify the efficacy of the derived approach.
