Coordinating Model Predictive Control of Transport and Supply Water Systems

Abstract

Transport and supply water networks are two types of systems which have received a significant amount of attention in the recent years. Issues on how to obtain the best performance for a given transport or supply water systems, or how to coordinate interactions between them are still open and need more research. This chapter presents a hierarchical Model Predictive Control (MPC) scheme with a supervisor that coordinates transport and supply water systems. First, a two-level hierarchical control structure resulting from a functional decomposition of water network is briefly presented. Inside each hierarchy, a MPC controller is used. In the two-level hierarchy, a supervisory coordinating mechanism is used to generate control strategies which consider objectives at different time scales. The first level, in charge of managing the transport system, works in a daily scale in order to achieve the global management policies for the transport over water (e.g., navigation, vessels and barges) in different rivers and balance management of different reservoirs. The second level, in charge of managing the supply system, works in a hourly scale and manipulates actuator (pumps and valves) set-point to satisfy the local water supplying objectives (e.g.,minimizing economic cost, handling emergency storage and smoothing actuator operation). The results of the modelling will be applied to the Catalunya Regional Water Network and based on an aggregate model.

Perspectives on Transport of Water versus Transport over Water

“…-Centralized: Uncertain control, delay-aware control, multi-objective control, nonlinear iterative control, predictive control, (automatically tuned) PI, nonlinear MPC, event-driven control, decentralized PI, optimization-based control, fault tolerant control [2,4,13,16,17, 21] -Distributed: single level, multi-level / hierarchical [11,17,18] • Operations research techniques (planning): scheduling, routing, mixed-integer optimization [3,21] • Integrated control and scheduling [3,20] • Economical analysis [8,22] • Proposal validation: Virtually in simulation studies, physical lab experiments, gaming for education [7,16,22] Details on all the above mentioned problems and methods, as well as their relation to the common framework of transport of water and transport over water are found in the provided references.…”

“…• Problems with a focus on transport of water -Improving water quality; removing algae for efficient water transport; effectively transporting sediment through water transport systems [2] -Optimally handing water quantity; avoiding too much or too little water (avoiding floods and droughts); delivering water at the right time at the right place [16,19] • Problems with a focus on transport over water -Increasing safety of navigation in transport over water; improving ship manoeuvring; keeping ships efficiently at specific positions via dynamic positioning [5][6][7]9] -Enhancing sustainability; decreasing energy consumption of transport over water systems; determining optimal power configuration for vessels [6,12] -Improving the logistics of transport over water; estimating the travel times accurately; modeling the traffic in transport over water systems [3,8,12,14] • Problems of a more generalized nature -Addressing the tradeoffs at different space scales; modeling whole networks at macroscopic perspective; modeling transport of and over water at smaller microscale scales [2, 10, 14] -Taking into account explicitly uncertainties; modeling and preparing for variations in currents, winds, social influences, system understanding [1,7,10,12,18,20,21] -Benefitting from the interaction between humans and automated systems [10,18] -Increasing the cooperation in transport of and over water systems; reactivating the transport over water market [12,20,22] • Problems focusing on the interaction -Balancing conflicting objectives of optimal delivery of water versus optimal navigation over water [16] -Designing the interactions among ship-waterway physics, river-wetland connections, river-waterway-canal interaction [7,8,14] The methods that are used to address these problems are a clear indication of the multidisciplinary nature of the domain considered:…”