This chapter addresses the scheduling problem of a sensor that constantly collects information from multiple sites. In the existing literature, the problem is solved by probabilistic approaches, potentially generating...
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ISBN:
(纸本)9783540743545
This chapter addresses the scheduling problem of a sensor that constantly collects information from multiple sites. In the existing literature, the problem is solved by probabilistic approaches, potentially generating schedules in which a site is not visited for a long time. To overcome this deficiency, this chapter presents a deterministic approach formulated as an integer linear program. Upon showing that the problem is NP-Hard, the chapter develops valid lower and upper bounds and proposes two constructive heuristic methods. Tested via an extensive computational study, the heuristic methods axe proven efficient and effective in solving the problem.
A multi-stage nonlinear model predictive controller is derived for the real-time coordination of multiple aircraft. In order to couple the versatility of hybrid systems theory with the power of NMPC, a finite state ma...
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ISBN:
(纸本)9783540726982
A multi-stage nonlinear model predictive controller is derived for the real-time coordination of multiple aircraft. In order to couple the versatility of hybrid systems theory with the power of NMPC, a finite state machine is coupled to a real time optimal control formulation. This methodology aims to integrate real-time optimal control with higher level logic rules, in order to assist mission design for flight operations like collision avoidance, conflict resolution, and reacting to changes in the environment. Specifically, the controller is able to consider new information as it becomes available. Stability properties for nonlinear model predictive control are described briefly along the lines of a dual-mode controller. Finally, a small case study is presented that considers the coordination of two aircraft, where the aircraft are able to avoid obstacles and each other, reach their targets and minimize a cost function over time.
This paper gives an overview of a framework for analyzing hybrid dynamical systems. The emphasis is on modeling assumptions that guarantee robustness. These conditions lead to a general invariance principle and to res...
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ISBN:
(纸本)9783540707004
This paper gives an overview of a framework for analyzing hybrid dynamical systems. The emphasis is on modeling assumptions that guarantee robustness. These conditions lead to a general invariance principle and to results on the existence of smooth Lyapunov functions (converse theorems) for hybrid systems. In turn, the stability analysis tools motivate novel hybrid control algorithms for nonlinear systems.
A nonlinear model predictive control (NMPC) formulation is used to prevent an exothermic fed-batch chemical reactor from thermal runaways even in the case of total cooling failure. Detailed modeling of the reaction ki...
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ISBN:
(纸本)9783540726982
A nonlinear model predictive control (NMPC) formulation is used to prevent an exothermic fed-batch chemical reactor from thermal runaways even in the case of total cooling failure. Detailed modeling of the reaction kinetics and insight into the process dynamics led to the formulation of a suitable optimization problem with safety constraints which is then successively solved within the NMPC scheme. Although NMPC control-loops can exhibit a certain degree of inherent robustness, an explicit consideration of process uncertainties is preferable not only for safety reasons. This is approached by reformulating the open-loop optimization problem as a min-max problem. This corresponds to a worst-case approach and leads to even more cautious control moves of the NMPC in the presence of uncertain process parameters. All results are demonstrated in simulations for the esterification process of 2-butyl.
This paper discusses the implementation of nonlinear model predictive control on continuous industrial polymer manufacturing processes. Two examples of such processes serve to highlight many of the practical issues fa...
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ISBN:
(纸本)9783540726982
This paper discusses the implementation of nonlinear model predictive control on continuous industrial polymer manufacturing processes. Two examples of such processes serve to highlight many of the practical issues faced and the technological solutions that have been adopted. An outline is given of the various phases of deploying such a solution, and this serves as a framework for describing the relevant modeling choices, controller structures, controller tuning, and other practical issues.
We will in this paper highlight our experience with NMPC. In our context NMPC shall mean the use of a nonlinear mechanistic model, state estimation, and the solution of an online constrained nonlinear optimisation pro...
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ISBN:
(纸本)9783540726982
We will in this paper highlight our experience with NMPC. In our context NMPC shall mean the use of a nonlinear mechanistic model, state estimation, and the solution of an online constrained nonlinear optimisation problem. Our reference base is a number of applications of NMPC in a variety of processes. We discuss the use of mechanistic models in NMPC applications and in particular the merits and drawbacks of applying such models in online applications. Further, we focus on state estimation, and the use of Kalman filters and moving horizon estimation. Finally, we consider the design of the optimization problem itself and implementation issues.
This chapter concerns the use of control theory to analyze some characteristic properties of biological systems involving limitations such as non-negativeness of variables and physical limitations. A biological system...
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ISBN:
(纸本)9783540719878
This chapter concerns the use of control theory to analyze some characteristic properties of biological systems involving limitations such as non-negativeness of variables and physical limitations. A biological system may be studied at different levels from the genes expression to the cells, through proteins levels or pathways. In this chapter, some interesting features related to constrained systems are recast to analyze and control biological systems at the level of cells, which aggregate at a macroscopic level interactions among proteins, RNA, DNA... based on the key notion of positively invariant sets.
This paper surveys recent work of the author with several collaborators, principally Feng Lin, Weilin Wang, and Tae-Sic Yoo;they are kindly acknowledged. Decentralized control of discrete event systems, where local co...
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ISBN:
(纸本)9783540707004
This paper surveys recent work of the author with several collaborators, principally Feng Lin, Weilin Wang, and Tae-Sic Yoo;they are kindly acknowledged. Decentralized control of discrete event systems, where local controllers cannot explicitly communicate in real-time, is considered in the first part of the paper. Then the problem of real-time communication among a set of local discrete-event controllers (or diagnosers) is discussed. The writing is descriptive and is meant to inform the reader about important conceptual issues and some recently-completed or on-going research efforts.
We introduce two conceptual models for wireless sensing and control with power-limited sensors and controllers. The limited battery power of the wireless device is captured in the models by imposing hard constraints o...
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ISBN:
(纸本)9783540707004
We introduce two conceptual models for wireless sensing and control with power-limited sensors and controllers. The limited battery power of the wireless device is captured in the models by imposing hard constraints on either the number of available transmissions the device can make, or on the number of cycles it can stay awake. Such hard constraints can be viewed as a measurement budget, under which estimation or control policies will have to be developed over a given decision horizon. Among the two representative models studied here, the first one is one of optimal scheduling of a finite measurement budget for a Gauss-Markov process over an observation horizon. The second one is an optimal estimation problem where the number of transmissions the wireless sensor can make is limited to a number, M, which is less than the observation horizon, N. It is shown that both problems can be solved by employing dynamic-programming type arguments, and their solutions have a threshold characterization.
This paper provides an expository introduction to monotone and near-monotone biochemical network structures. Monotone systems respond in a predictable fashion to perturbations, and have very robust dynamical character...
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ISBN:
(纸本)9783540719878
This paper provides an expository introduction to monotone and near-monotone biochemical network structures. Monotone systems respond in a predictable fashion to perturbations, and have very robust dynamical characteristics. This makes them reliable components of more complex networks, and suggests that natural biological systems may have evolved to be, if not monotone, at least close to monotone. In addition, interconnections of monotone systems may be fruitfully analyzed using tools from control theory.
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