Papers by Author: Tao Zhang

Abstract: Model for drive system of four-wheel-drive electric vehicle was investigated. By combing the balance equation for the vehicle movement with the equation of motor mechanical properties, a mathematical model of driving system of electric vehicle was established, PI control strategy was used for the optimal control and the model was simulated by the software Matlab/Simulink. The simulation results show that the mathematical model of driving system of the electric vehicle can represent the vehicle running states accurately.

Abstract: This paper presents a Bayesian denoising method based on an anisotropic Markov Random Field (MRF) model in wavelet domain in order to improve the image denoising performance and reduce the computational complexity. The classical single-resolution image restoration method using MRFs and the maximum a posteriori (MAP) estimation is extended to the wavelet domain. To obtain the accurate MAP estimation, a novel anisotropic MRF model is proposed under this framework. As compared to the simple isotropic MRF model, this new model can capture the intrascale dependencies of wavelet coefficients significantly better. Simulation results demonstrate our proposed method has a good denoising performance while reducing the computational complexity.

Abstract: A static output feedback (SOF) control schemes are proposed. The basic idea of it is to construct piecewise quadratic Lyapunov function and introduce a dissipation inequality to guarantee the system energy dissipation. It is shown that the controller analysis or the synthesis problem can be casted as convex optimization problem, and the controller can be obtained by solving a set of linear matrix inequalities. The designed controllers not only guarantee the stability of the closed-loop systems, but also obtain the disturbance attenuation ability.

Abstract: A design method of LS-SVM based stable adaptive controller is proposed for a class of nonlinear continuous systems with unknown nonlinear function in this paper. Due to the fact that the control law is derived based on the Lyapunov stability theory, the scheme can not only solve the tracking problem of this class of nonlinear systems, but also it can guarantee the asymptotic stability of the closed systems, which is superior to many LS-SVM based control schemes. The effectiveness of the proposed scheme is demonstrated by simulation results.

Abstract: In this paper, the stability of systems with interval time-varying delay is investigated. The time delay varies in an interval. By employing a new and tighter integral inequality and constructing an appropriate type of Lyapunov functional, the delay-dependent stability criteria are derived. Because neither any model transformation nor free weighting matrices are employed in the theoretical derivation, the developed stability criteria significantly improve and simplify the existing stability conditions.