Article
Transactions of the Institute of
Measurement and Control
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DOI: 10.1177/0142331214528970
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Constrained distributed model
predictive control for state-delayed
systems with polytopic uncertainty
description
Langwen Zhang, Jingcheng Wang, Yang Ge and Bohui Wang
Abstract
Although distributed model predictive control (MPC) has received significant attention in the literature, the robustness of distributed MPC with respect
to model uncertainties and state delays has not been explicitly addressed. In this paper, a novel approach to design robust distributed MPC is proposed
for polytopic uncertain systems with state delays. The algorithm requires decomposing the entire system into M subsystems and solving M linear matrix
inequality optimization problems to minimize an upper bound on a robust performance objective for each subsystem. An iterative on-line algorithm for
robust distributed MPC is developed to coordinate the distributed controllers. The algorithm is a flexible structure of robust control, which allows the
independent computation of the state feedback laws for the subsystems. Convergence and robust stability of the proposed distributed MPC are ana-
lysed. Two numerical examples are carried out to demonstrate the effectiveness of the proposed algorithm.
Keywords
Distributed model predictive control, polytopic uncertain systems, constrained control, state-delayed systems
Introduction
It is known that model uncertainties and state delays cannot
be avoided in practices, such as chemical processes, where the
model predictive control (MPC) technique has been widely
applied. In the context of a networked environment, state
delays become extremely important in MPC design and stabi-
lity. There has been an increasing interest in robust control of
uncertain state-delay systems in control literatures (Ding,
2010; Ding and Huang, 2007; Kothare et al., 1996; Li and Xi,
2011). In Kothare et al. (1996), the authors suggested extend-
ing their robust MPC algorithm to time-delay systems.
However, they have not given the details for implementation.
Jeong and Park (2005) presented a robust MPC algorithm for
uncertain time-varying systems with only one state delay.
Ding and Huang (2007) provided an extensive study for the
synthesizing robust MPC of Kothare et al. (1996). The results
were further extended to robust MPC for polytopic uncertain
systems with time-varying delays by Ding et al., 2008. To
investigate the multiple time-delay systems, Ding (2010) pro-
vided a robust MPC algorithm and Li and Xi (2011) provided
a constrained feedback robust MPC for polytopic uncertain
systems with time delays. Lu et al. (2013) were concerned with
probability-based constrained MPC for systems with both
structured uncertainties and time delays, where a random
input delay and multiple fixed state delays were included.
The systems are becoming more and more complex for
system analysis and controller design (Lee, 2011). It is diffi-
cult to control these systems with a centralized MPC structure
due to the computational complexity and communication
bandwidth limitations (Scattolini, 2009). There has been
increasing interest in decomposing a whole plant into several
subsystems, and then solving each subsystem with coordina-
tion to reach a global performance. In general, there are two
different approaches to handle the distributed MPC problem,
namely non-cooperative and cooperative distributed MPC.
The non-cooperative MPC algorithm attempts to solve the
distributed MPC controller via optimizing a local perfor-
mance index. For example, Jia and Krogh (2002) provided a
non-cooperative distributed MPC in which each subsystem
optimized a local cost function. The subsystems made coordi-
nation via communication. Mercango
¨
z and Doyle (2007) pro-
posed an iterative implementation of a similar distributed
MPC scheme and applied it to a four-tank process. These
non-cooperative distributed MPC approaches only reach a
Nash-optimization (Li et al., 2005). The cooperative distribu-
ted MPC approach is based on subsystem collaboration, in
which each subsystem cooperates to optimizing a global
Department of Automation, Shanghai Jiao Tong University, and Key
Laboratory of System Control and Information Processing, Ministry of
Education of China, China
Corresponding author:
Jingcheng Wang, Department of Automation, Shanghai Jiao Tong
University, and Key Laboratory of System Control and Information
Processing, Ministry of Education of China, Shanghai 200240, China.
Email: jcwang@sjtu.edu.cn
at Shanghai Jiaotong University on December 18, 2014tim.sagepub.comDownloaded from