Flatness‐based control approach to networked control under sensor delays

Abstract

A new control method based on differential flatness theory is developed in this article, aiming at solving the problem of networked control under sensor delays. A sensor network comprising N sensors and N control inputs is considered. Time delays between the control inputs and the system's outputs (sensor readings) are taken into account. Using the principle of dynamic extension, which means that by considering certain control inputs and their derivatives as additional state variables, a state-space description for the networked control system is obtained. It is proven that the dynamic model of the networked control system is a differentially flat one. This enables its transformation into a linear canonical and decoupled form, for which the design of a stabilising feedback controller becomes possible. The proposed feedback controller is of proven stability and assures fast and accurate tracking of the reference setpoints by the outputs of the network control system. Moreover, by using a Kalman-filter-based disturbances' estimator, it becomes possible to estimate in real time and compensate for parametric uncertainty, external perturbation inputs, and variation in sensor delays that may appear in the networked control system.