Bao-Lin Zhang

Sliding mode control with mixed current and delayed states for offshore steel jacket platforms

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.

An Overview and Deep Investigation on Sampled-Data-Based Event-Triggered Control and Filtering for Networked Systems

This paper provides an overview and makes a deep investigation on sampled-data-based event-triggered control and filtering for networked systems. Compared with some existing event-triggered and self-triggered schemes, a sampled-data-based event-triggered scheme can ensure a positive minimum inter-event time and make it possible to jointly design suitable feedback controllers and event-triggered threshold parameters. Thus, more attention has been paid to the sampled-data-based event-triggered scheme. A deep investigation is first made on the sampled-data-based event-triggered scheme. Then, recent results on sampled-data-based event-triggered state feedback control, dynamic output feedback control,

Delayed non-fragile H∞ control for offshore steel jacket platforms

H_\infty

Neuronal State Estimation for Neural Networks With Two Additive Time-Varying Delay Components

filtering for networked systems are surveyed and analyzed. An overview on sampled-data-based event-triggered consensus for distributed multiagent systems is given. Finally, some challenging issues are addressed to direct the future research.

Optimal tracking control with feedforward compensation for offshore steel jacket platforms with active mass damper mechanisms

This paper is concerned with a delayed non-fragile H ∞ control scheme for an offshore steel jacket platform subject to self-excited nonlinear hydrodynamic force and external disturbance. By intentionally introducing a time-delay into the control channel, a delayed robust non-fragile H ∞ controller is designed to reduce the vibration amplitudes of the offshore platform. The positive effects of the time delays on the non-fragile H ∞ control for the offshore platform are investigated. It is shown through simulation results that (i) the proposed delayed non-fragile H ∞ controller is effective to attenuate the vibration of the offshore platform; (ii) the control force required by the delayed non-fragile H ∞ controller is smaller than that required by the delay-free non-fragile H ∞ controller; (iii) the time delays can be used to improve the control performance of the offshore platform.

Wave Attenuating delay-dependent H ∞ control for offshore platforms with parameter uncertainties

This paper is concerned with the state estimation for neural networks with two additive time-varying delay components. Three cases of these two time-varying delays are fully considered: 1) both delays are differentiable uniformly bounded with delay-derivative bounded by some constants; 2) one delay is continuous uniformly bounded while the other is differentiable uniformly bounded with delay-derivative bounded by certain constants; and 3) both delays are continuous uniformly bounded. First, an extended reciprocally convex inequality is introduced to bound reciprocally convex combinations appearing in the derivative of some Lyapunov–Krasovskii functional. Second, sufficient conditions are derived based on the extended inequality for three cases of time-varying delays, respectively. Third, a linear-matrix-inequality-based approach with two tuning parameters is proposed to design desired Luenberger estimators such that the error system is globally asymptotically stable. This approach is then applied to state estimation on neural networks with a single interval time-varying delay. Finally, two numerical examples are given to illustrate the effectiveness of the proposed method.

Network-based active control for offshore steel jacket platforms

This paper presents the optimal tracking control methodology for an offshore steel jacket platform subject to external wave force. Based on a dynamic model of an offshore steel jacket platform with an active mass damper mechanism and a linear exogenous system model of the external wave force on the offshore platform, an optimal tracking control scheme with feedforward compensation is proposed to attenuate the wave-induced vibration of the offshore platform. A feedforward and feedback optimal tracking controller (FFOTC) can be obtained by solving an algebraic Riccati equation and a Sylvester equation, respectively. It is demonstrated that the wave-induced vibration amplitudes of the offshore platform under the FFOTC are much smaller than the ones under the feedback optimal tracking controller (FOTC) and the feedforward and feedback optimal controller (FFOC). Furthermore, the required control force under the FFOTC is smaller than the ones under the FOTC and the FFOC.

Network-based control for offshore steel jacket platform subject to wave-induced force

This paper is concerned with delay-dependent robust H∞ control for an offshore steel jacket platform subject to wave force. By taking into account the variations of the structural natural frequency and damping ratio, and time-varying control delay, an uncertain time-delay dynamic modal of the offshore platform is established first. Then a delay-dependent robust H∞ control scheme is proposed to attenuate the wave-induced vibration of the platform. A delay-dependent robust H∞ controller is obtained in terms of the solvability of a nonlinear minimization problem. Simulation results show that though there exist time-varying control delay and parameter uncertainties in the system, the designed controller can effectively attenuate the vibration of the offshore platform and keep the stability of the system.

Delayed non-fragile H ∞ control for offshore steel jacket platforms

This paper is concerned with network-based control for an offshore steel jacket platform with an active tuned mass damper mechanism. A network-based dynamic model of the offshore platform is presented first. Then, a network-based state feedback control scheme is developed. Based on a proposed Lyapunov-Krasovskii functional, a delay-dependent stability criterion for the offshore platform system is derived, and a sufficient condition for the existence of the network-based controller is developed. It is found through simulation results that the oscillation amplitudes of the offshore steel jacket platform under the network-based feedback controller are smaller than the ones under the nonlinear controller, and the control force required by the former is much smaller than the one by the latter.

Sliding mode control for offshore steel jacket platforms

This paper is concerned with network-based control for an offshore steel jacket platform subject to nonlinear wave-induced force. A network-based dynamic model of the offshore platform is presented and a network-based state feedback control scheme is developed to reduce the internal oscillations of the offshore platform. Then the effect of a network-induced delay on the control performance of the offshore platform is investigated. It is found through simulation results that (i) the network-based state feedback controller is of a smaller gain in the sense of Euclidean norm than the state feedback controller without network setting, which means the network-based state feedback controller requires less control force; and (ii) the network-induced delay is of the positive effect on state feedback control of the offshore platform.