Lu Renquan

Delay-dependent robust H ∞ control for uncertain discrete singular time-varying delay systems based on a finite sum inequality

The problem of delay-dependent robust H∞ control for uncertain discrete singular time-varying delay systems is addressed in this paper. The uncertainty is assumed to be norm bounded. By establishing a finite sum inequality based on quadratic terms, a new delay-dependent bounded real lemma is derived and expressed in terms of linear matrix inequality(LMI). A suitable robust H∞ state feedback control law is presented, which guarantees that the resultant closed-loop system is regular, causal and stable with disturbance attenuation level γ for all admissible uncertainties. A numerical example is given to demonstrate the applicability of the proposed method.

Delay-dependent absolute stability criteria for Lur’e singular systems with time-varying delay

The problem of absolute stability for Lurpsilae singular systems with time-varying delay is presented. The uncertainty is assumed to be norm bounded. By establishing an integral inequality based on quadratic terms, which avoids employing both model transformation and bounding technique for cross terms, some delay-dependent absolute stability criteria are obtained and formulated in the form of linear matrix inequalities. Numerical examples are also given to show the effectiveness of the obtained results.

Exponential H ∞ guaranteed cost control for nonlinear stochastic delay systems

This paper investigates Hinfin guaranteed cost control for a class of Ito-type stochastic systems with time delays and nonlinear perturbations. Based on Lyapunov-Krasovskii method, a state-feedback guaranteed cost controller is proposed. The designed controller guarantees the resulting closed-loop system is stochastically exponentially mean-square stable with a prescribed Hinfin disturbance attenuation level, for all admissible nonlinear perturbations. Sufficient condition for the existence of desired controller is formulated in terms of a linear matrix inequality (LMI). Moreover, the design problem of the optimal exponential Hinfin guaranteed cost controller for the nonlinear stochastic delay systems is cast into a standard convex optimization problem with LMIs constraints. The effectiveness of the proposed method is demonstrated by a numerical example.

Minimization Method for Combined Sewage Overflow of Urban Drainage

The problem of the overflow of combined sewage is concerned with in this paper. The sewer’s discrete state‐space model of the hydraulics and predictive model are established to predict the future output at sampling time. Firstly, the model is corrected by the errors between value of observation and prediction. Secondly a quadratic function by comparing the predicted output with the reference trajectory is introduced to calculate the best flow rate. Finally, the minimal overflow of combined sewage is obtained in urban hydraulic system.

Robust H ∞ optimal speed control of linear DC motor

The speed control ability of DC motor is affected by parameter variations and disturbance torque. In this paper, based on a linear matrix inequality (LMI) approach, the robust Hinfin optimal control for DC motor with parameter variations is proposed, the stability and performance robustness are analyzed. In order to verify the validity of the proposed control scheme, simulation results are also presented, the results show that system has strong ability of preventing interference and high stability.