Dual scheduling and quantised control for networked control systems with communication constraints

Abstract

A novel integrated design scheme of average dwell time scheduling strategy, dynamic bandwidth allocation policy and quantised control for a collection of networked control systems (NCSs) with time delay and communication constraints is proposed in this paper. A scheduling policy is presented to accommodate the limitation of communication capacity which depends on the convergence rate of closed-loop system and divergence rate of open-loop plant. Linear programming technique is adopted to dynamically allocate bit rate for each node and the strategy is used to make trade-offs between the network utilisation and the control performance which provides an effective way of optimising the quality of control (QoC) and the quality of service (QoS) for NCSs. Mid-tread uniform quantisers update the quantisation rules according to the assignment of the bit rate and convert the quantised state into a kind of input saturation with bounded disturbances. Taking into account the effect of dual scheduling strategy and quantisation, the NCSs are modelled as discrete-time switched systems with bounded disturbances. Furthermore, a scheduling and quantised feedback control co-design procedure is proposed for the simultaneous stabilisation of the collection of networked subsystems. Finally, a simulation example is given to illustrate the effectiveness of the proposed method.

Keywords:

• networked control systems
• scheduling
• average dwell time
• linear programming
• communication constraints

Acknowledgements

The authors are grateful to the reviewers and the editors for their helpful comments and suggestions on this paper.

Additional information

Funding

This work was partially supported by Graduate Student Innovative Programme [grant number GSIP201408] in Nanjing University of Science and Technology, China.

Notes on contributors

Hui Lu

Hui Lu was born in Jiangxi Province, China. He received the BS degree in automatic control from Nanchang University, Jiangxi, China, in 2008. He is currently working toward the MS degree in school of Automation, Nanjing University of Science and Technology, Nanjing, China. His current research interests include networked control systems and multi-agent systems.

Chuan Zhou

Chuan Zhou received the PhD degree from Nanjing University of Aeronautics and Astronautics, P.R. China in 1999. Since 2001, he has been with Nanjing University of Science and Technology and he is a professor in the School of Automation. His research interests include network control systems, intelligent control and network routing and congestion control theory.