Delta-Modulator-Based Quantised Output Feedback Controller for Linear Networked Control Systems

Abstract

This article proposes a Δ -Modulator ( Δ -M) based quantised output feedback controller for linear networked systems. The proposed Δ -M is essentially a 2-level quantiser, in contrast to some of the existing quantisers such as 2p level ( p≥1 ) uniform-interval-nearest-neighbour quantiser, and offers various advantages which include lower design complexity, less noisy and lower cost. The three key components of the control system: the controller , the filter and the quantiser are designed to achieve the desired performance. The stability conditions of the Δ -M are derived and conditions for the existence of zig-zag behaviour in steady-state are determined. The performance of the proposed controller is illustrated through simulations considering practical communication network based on ZigBee protocol. The results of the simulation demonstrate that the proposed controller could effectively achieve desired performance under various imperfections of the practical communication network.

Keywords

• Δ-modulation
• quantised control
• networked control systems (NCSs)
• output feedback control