Showing papers by "Xian-Ming Zhang published in 2014"

Event-triggered dynamic output feedback control for networked control systems

Abstract: 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.

Sliding Mode Control With Mixed Current and Delayed States for Offshore Steel Jacket Platforms

Abstract: This paper is concerned with active control for an offshore steel jacket platform subjected to wave-induced force and parameter perturbations. An uncertain dynamic model for the offshore platform is first established, where uncertainties not only on the natural frequency and the damping ratio of both the offshore platform and the active tuned mass damper (TMD) but also on the damping and stiffness of the TMD are considered. Then, by intentionally introducing a proper time delay into the control channel, a novel sliding mode control scheme is proposed. This scheme uses information about mixed current and delayed states. It is shown through simulation results that this scheme is more effective in both improving the control performance and reducing control force of the offshore platform than some existing ones, such as delay-free sliding mode control, nonlinear control, dynamic output feedback control, and delayed dynamic output feedback control. Furthermore, it is shown that the introduced time delay in this scheme can take values in different ranges while the corresponding control performance of the offshore platform is almost at the same level.

New stability criterion using a matrix-based quadratic convex approach and some novel integral inequalities

Abstract: This study is concerned with the stability of a linear system with an interval time-varying delay. First, a new augmented Lyapunov-Krasovskii functional (LKF) is constructed, which includes three integral terms in the form of ∫ t-h t ( h - t )+) s ) j x T R j x(s) d s ( j )=) 1, 2, 3). Second, three novel integral inequalities are established to estimate the upper bounds of the integrals ∫ t-h t ( h - t )+) s ) j x T R j x(s) d s ( j )=) 0, 1, 2) appearing in the derivative of the LKF. Third, a matrix-based quadratic convex approach is introduced to prove not only the negative definiteness of the derivative of the LKF along with the trajectory of the system, but also the positive definiteness of the LKF. Finally, a novel delay-derivative-dependent stability criterion is formulated. The effectiveness of the stability criterion is shown through two numerical examples.

Network-Based Stabilization of Linear Systems via Static Output Feedback

Abstract: This paper is concerned with the problem of static output feedback control for networked systems with a logic zero-order-hold (ZOH). First, the networked closed-loop system is modeled as a discrete-time linear system with a time-varying delay, whose upper bound can be regarded as not only the admissible maximum delays induced by the network but also the admissible maximum number of packet dropouts between any two consecutive updating instants of ZOH. Then, in order to obtain a larger upper bound of the time-varying delay, a generalized finite-sum inequality is introduced, based on which, a less conservative stability condition is derived by incorporating with convex combination technique. By using the cone complementary linearization approach, the desired output feedback controllers can be designed by solving a nonlinear minimization problem subject to a set of linear matrix inequalities. Finally, some examples are given to show the effectiveness of the proposed method.

Co-design of event-triggered scheme and distributed H ∞ filters for networked systems with sensor networks

Abstract: This paper is concerned with the problem of event-triggered distributed H ∞ filtering for a class of networked systems with sensor networks First, an event-triggered scheme is introduced to select those necessary data packets to be transmitted for filter design As a result, communication and energy resources can be significantly saved while some certain system performance can be preserved Second, under the event-triggered scheme, a delay system model is established for distributed filtering error systems The Lyapunov-Krasovskii method is thus employed to formulate a linear matrix inequality based sufficient condition on the existence of suitable distributed H ∞ filters Third, a co-design algorithm for both distributed H ∞ filters and event-triggered parameters is presented in terms of solutions to a set of linear matrix inequalities Finally, a numerical example is given to illustrate the effectiveness of the proposed method