Stabilization of NCSs: asynchronous partial transfer approach

In this paper, a framework for stabilization of networked control systems with limited data rates is presented. The key technology is that instead of sending the complete state vector (for an n-dimensional system, which means a data array with n items) to the network, we only send one item of a nonsingular transform of the state vector at each step. The main advantage of our mechanism is dramatically reducing the amount of the data sent to the network. In order to implement such a technology, in our framework, two auxiliary instruments are included into the overall closed-loop state feedback system over the network. One instrument is used as an encoder, which runs a transform of the system state and sends the items of the transformed state vector in turn. The other takes the role as a decoder, which receives items of the transformed state vector from the network and reconstructs the state vector for the controller. It is shown that if the plant is stabilizable via direct state feedback control, then it can be stabilized with the same controller under our framework over the network.

I. Introduction

In distributed control systems, a feedback control loop is closed through a network. Distributed control systems with networks are called networked control systems(NCSs). The use of a data network in a control loop has gained increasing attention in recent years due to its cost effective and flexible applications. The advantages of NCSs include drastic decreasing the number and the total length of cables, easiness of system diagnosis and maintenance, and increasing system agility. Thus, many industrial applications, such as robotic systems, jacking systems for train cars, networks on automobiles, and process control systems can be reconstructed and modelled as NCSs.