Fei Shumin

Direct Fuzzy Tracking Control of a Class of Nonaffine Stochastic Nonlinear Systems with Unknown Dead-Zone Input

Abstract In this paper, a direct adaptive fuzzy tracking control scheme is presented for a class of stochastic nonaffine uncertain nonlinear systems with unknown dead-zone input. Based on the first-type fuzzy logic systems online approximation capability, a direct adaptive fuzzy tracking controller is developed by using the backstepping approach. It is proved that the design scheme ensures that all the error variables are bounded in probability while the mean square tracking error becomes semiglobally uniformly ultimately bounded(SGUUB) in an arbitrarily small area around the origin. Simulation results show the effectiveness of the control scheme.

On Exponential Stability of Switched Systems with Delay: Multiple Lyapunov Functions Approach

The switched system composed of several linear time-delay systems is considered. The problem is to find the constraint conditions on subsystems and switching sequences to preserve the exponential stability. The multiple Lyapunov functions approach is generalized to the time-delay case, it is verified that the specified stability criterion for subsystems implies the exponential stability of whole system whenever the segments between two consecutive switching instants are greater than a prescribed constant. Our results include the correspondent conclusion of stability analysis in the case without after-effect. Numerical examples are given to demonstrate our results.

Cluster Synchronization in Hybrid Coupled Discrete-Time Delayed Complex Networks

This paper studies the exponential cluster synchronization in arrays of coupled discrete-time dynamical networks with time-varying delay, in which the hybrid coupling is involved. Through choosing two improved Lyapunov—Krasovskii functionals, some delay-dependent sufficient conditions are presented based on reciprocal convex technique and Kronecker product. These criteria are presented in terms of LMIs and their feasibility can be easily checked by resorting to Matlab LMI Toolbox. Moreover, the addressed system can include some famous network models as its special cases and the effective techniques are used, which can extend some earlier reported results. Finally, the effectiveness of the proposed methods can be further illustrated with the help of two numerical examples.

A predictive functional control algorithm for multivariable systems with time-delay

To improve the dynamic characteristics and the coupling capability, a new predictive functional control algorithm is proposed for strong coupling multivariable systems with time delay, which combines predictive functional control and decoupling control. First, a decoupling control algorithm is proposed, in which first-order models with time delay are established by analyzing the amplitude-frequency and phase-frequency characteristics of the decoupled subject. Then, a controller is designed for the single-variable subjects after decoupling based on the principles of predictive functional control. The simulation results show that this proposed algorithm has less online computation time and faster tracking. It can provide a more effective control for complex multivariable systems.

Robust control with observer of internet-based teleoperation

Time delay reduces significantly ability of teleoperation. This problem becomes especially seriously in case of Internet-based teleoperation, when the time delay is variable. To overcome the trouble, time forward observer is used to predict the state of the slave. Moreover, force, position and velocity feedback is proposed to ensure that the system is robust asymptotically stable and transparent. The results of the experiment show effectiveness of this method.

Enhanced model reference adaptive backstepping control of permanent magnet synchronous generator equipped wind energy conversion system with stator parameters varying

Based on model reference adaptive backstepping control (MRABC) method, an enhanced MRABC (EMRABC) scheme is proposed for permanent magnet synchronous generator (PMSG) equipped direct-drive wind energy conversion system (WECS) with stator parameters varying. The algorithm is robust to aerodynamic moment disturbance and stator resistance and inductance uncertainties. Comparing with MRABC, theoretical analysis and simulation results show the validity of the proposed approach.

On the controllability and the stabilizability of control delay systems

Discusses the controllability and the stabilizability of the control delay systems, and then gives some results. Particularly for the general control delay system, gives the equivalence condition of the controllability and the stabilizability.

A target group tracking algorithm for wireless sensor networks using azimuthal angle of arrival information

In this paper, we explore the technology of tracking a group of targets with correlated motions in a wireless sensor network. Since a group of targets moves collectively and is restricted within a limited region, it is not worth consuming scarce resources of sensors in computing the trajectory of each single target. Hence, in this paper, the problem is modeled as tracking a geographical continuous region covered by all targets. A tracking algorithm is proposed to estimate the region covered by the target group in each sampling period. Based on the locations of sensors and the azimuthal angle of arrival (AOA) information, the estimated region covering all the group members is obtained. Algorithm analysis provides the fundamental limits to the accuracy of localizing a target group. Simulation results show that the proposed algorithm is superior to the existing hull algorithm due to the reduction in estimation error, which is between 10% and 40% of the hull algorithm, with a similar density of sensors. And when the density of sensors increases, the localization accuracy of the proposed algorithm improves dramatically.

Moving target detection in image sequences

A novel and effective approach to the global motion estimation and moving object extraction is proposed in this paper. Firstly, the translational motion model was used by the fact that complex motion can be decomposed as a sum of translational components. Then in this application, the edge gray horizontal and vertical projections were used as the block matching feature for the motion vector estimation. The proposed algorithm reduces the motion estimation computations by calculating the one-dimensional vector rather than the two-dimensional ones. Once the global motion is robustly estimated, relatively stationary background can be almost completely eliminated through inter-frame difference method. To achieve an accurate object extraction result, the higher-order statistics (HOS) algorithm was used to discriminate background and moving object. Experiments have shown a robust result for global motion estimation and object extraction.

Design and simulation of fuzzy sliding-mode robust controller for grid-connected photovoltaic system

A fuzzy sliding-mode robust controller with feed forward compensation is designed for grid-connected photovoltaic system. First, a integral sliding-mode controller is designed by exponential approach law to accelerate the systems starting phase, and for improving the stability of the system, the output of the sliding-mode controller is soften by fuzzy controller to reduce the flicking of the sliding-mode controller. Furthermore, a feed forward compensation is introduced to further enhance the systems dynamical performance. Finally, the simulation is performed with the help of Matlab/Simulink & SimPowerSystems. Simulation results show that the novel control method can successfully realize the vector decoupling of the d, q axis output current of the inverter, and compared with the sliding-mode controller, it have better dynamic and static performances and robustness under the fast change of external environment.