Gain-scheduled control of nonlinear sampled-data systems: A Wirtinger-based approach

This paper addresses the design of gain-scheduled state-feedback controllers for sampled-data nonlinear systems, aiming at the minimization of the L2-gain. A description of nonlinear systems based in polynomial quasi-linear parameter-varying models is employed. Sucient conditions for the synthesis of sampled-data controllers are derived in terms of polynomial linear matrix inequalities, using Wirtinger's Inequality and considering Lyapunov-Krasovskii functionals. The designed controllers ensure both closed-loop stability and guaranteed L2-gain costs. The eectiveness of the proposed approach is assessed through numerical simulations.

Pinning synchronization control of complex networks with partial couplings

In this article, the pinning synchronization problem of complex networks with a target node via sampled-data communications is considered. Due to partial couplings among the nodes in complex networks, a decoupling method is adopted to investigate each channel of complex networks independently. By constructing a time-dependent Lyapunov function, it is proved that the pinning synchronization of complex networks with a target node can be achieved if the control parameters are appropriately selected. Furthermore, further study is needed to investigate the pinning synchronization of complex networks in the presence of constant delay. A novel criterion is obtained using Jensen’s inequality and Wirtinger’s inequality. It is worth noting that the lower and upper bounds of the sampling intervals can be calculated by linear matrix inequality box of MATLAB. Theoretical results are well verified through a numerical simulation.

Sampled-Data Control of Large-Scale Fuzzy Interconnected Systems

This chapter aims to study the sampled-data stabilization for large-scale fuzzy interconnected systems. We use two approaches to design the decentralized fuzzy sampled-data controller: Wirtinger's inequality and scaled small gain (SSG) theorem. Our aim is to derive the co-design consisting of the controller gains and sampled period in terms of a set of LMIs. Also, we consider the distributed sampled-data control problem, where the sampling periods among all subsystems may be different, and the actuator in each subsystem is time-driven. Finally, two simulation examples are provided to validate the advantage of the proposed methods.

Robust Stochastic Sampled-Data H∞ Control for a Class of Mechanical Systems With Uncertainties

This paper considers a class of mechanical systems with uncertainties appearing in all the mass, damping, and stiffness matrices. Two cases, linear fractional and randomly occurring uncertainty formulations, are considered. Since sampled-data controllers have an advantage of implementing with microcontroller or digital computer to lower the implementation cost and time, a robust stochastic sampled-data controller is considered with m sampling intervals whose occurrence probabilities are given constants and satisfy Bernoulli distribution. A discontinuous type Lyapunov functional based on the extended Wirtinger's inequality is constructed with triple integral terms and sufficient conditions that promises the robust mean square asymptotic stability of the concerned system are derived in terms of linear matrix inequalities (LMIs). In an aim to reduce the conservatism, a newly introduced concept called the second-order reciprocally convex approach is employed in deriving the bound for some cross terms that arise while maneuvering the derivative of Lyapunov functional. The obtained LMIs can be easily solved through any of the standard available software. Finally, numerical examples are given to verify the effectiveness of the proposed theoretical results.

Lower Bounds of Periods of Periodic Solutions for a Class of Differential Equations with Variable Delays

Based on generalized Wirtinger's inequality, periods of periodic solutions of the nonautonomous differential equations with variable delays are investigated. Based on Hölder inequality, lower bounds of periods of periodic solutions for a class of functional differential equations with variable delays are obtained by a simple method.