Robust Fuzzy Control of Network-Type Re-Entrant Manufacturing Systems With Communication Delays

The robust fuzzy control problem for a category of network-type re-entrant manufacturing systems (RMSs) is explored in this paper. A continuum model is first employed to represent the RMSs with external disturbances and time-varying communication delays in terms of a nonlinear hyperbolic partial differential equation (PDE) model. The nonlinear model is then reformulated in the framework of a T-S fuzzy model. A novel Lyapunov-Krasovskii-type stability theorem is proposed for the concerned PDEs with delays, extending the classical Lyapunov-Krasovskii framework to delayed PDE systems. Using the proposed stability theorem, LMI-based conditions are developed for stability analysis and control synthesis of the closed-loop RMSs under external disturbances and time-varying delays, which demonstrates effective alignment of production output with market demand despite environmental perturbations. At last the results of a simulation validate the developed control approach.