a cyber-physical system for distributed real-time control ...€¦ · a cyber-physical system for...

A Cyber-Physical System for Distributed Real-Time Control of Urban Drainage

Networks in Smart Cities

Andrea Giordano, Giandomenico Spezzano, Andrea Vinci ICAR - CNR

Rende (CS), Italy

Giuseppina Garofalo, Patrizia Piro Dipartimento Ingegneria Civile- Indirizzo Idraulica

Università della Calabria Rende (CS), Italy

http://www.unical.it/

Background

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Sewer system

• The magnitude and the frequency of

flooding in urban areas are likely to

increase due to

• climate change

• expanding urbanization

• In current practices, engineers and

administrators focus their attention on

flooding phenomena due to rivers inside

the cities

• Conversely, There is not enough attention

toward flooding triggered by overload

conditions occurring in the sewer system

(sewer flooding).

• Flooding phenomena give rise to

potential risks to human life, economic

assets and the environment, etc.

IDCS 2014, Sept 22 – 24, Calabria, Italy

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Sewer system

Drains

Road surface

Flooding phenomenon


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Sewer system Drains

Road surface

Flooding phenomenon


“Smart” Gates

5 DSRT 2011, September 4 - 7, Salford, UK IDCS 2014, Sept 22 – 24, Calabria, Italy

electronically adjustable

gates. They allow you

dynamically changing the

flow of the water

Distributed real-time control

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Real time control: ◦ Reading from sensors

◦ Elaborating information (as soon as possible)

◦ Actuating on the gates

Issues related on ‘centralized’ control ◦ Need for comprehensive mathematical model of the whole hydraulic

network

◦ Need for communication between each sensor and gate and the centralized control

◦ the huge amount of the incoming data gives rise to real time constraint violation

Proposed approach: fully distributed: ◦ Computational nodes spread across the drainage network (RaspBerry)

◦ Only short-range communications are required

◦ Enabling Agent-based e Swarm Intelligence


Drainage network

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A drainage network is made up of: ◦ conduits, i.e. pipes where water

flows

◦ Inlet nodes, i.e. water entry points (manhole)

◦ Outlet nodes, i.e. exit points where water is discharged into a river, lake, reservoir and so forth

◦ Junctions, i.e intersection points for conduits

A whole drainage network of a city can be broken down in a set of not connected tree-like structured drainage networks which own only on outlet node


Drainage network

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A drainage network is defined in a recursive way: it is made up of a main channel into which recursively defined (sub)network discharge. The recursive process stops when reaching the Most simple Drainage Network (MSDN) made up of only a conduit and an inlet node.


Drainage network

9 IDCS 2014, Sept 22 – 24, Calabria, Italy

Generated networks


Gates position

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The gates are inserted at the start of each branch, i.e. between the junctions of the main channel and the sub-networks


Gate-agents

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One agent per gate

One agent per outlet node

The whole problem become: «for each network, each agent has to tune its gate in order to ensure that filling levels of the conduits are balanced as much as possible»


agent algorithm

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agents continuously execute two tasks: ◦ Task 1: Figuring out the average of the water level in the specific network

◦ Task 2: triggering specific gates in order to bring the water level closer to that average


Task1: Gossip-based algorithm

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Nodes own such numerical values

The goal is to compute global average even if each node is able to communicate only with neighbour nodes

Each node holds the current “local” average value (initially sets to the measured value)

These local average values are continuously exchanged among neighbor nodes which update their local averages by applying the average operator

It can be proved that the algorithm converges to the global average value after an enough steps *

The algorithm ensures fault tolerance and adaptivity

*Jelasity M., Montresor A., Babaoglu O., Gossip-based aggregation in large dynamic networks, ACM

Transactions on Computer Systems 23, 3, 219 - 252, 2005.


Task2: how to tune the gate?

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Even though we know the optimal water level to set, we don’t know how to adjust gates so as to get it


PID Controller

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The average value computed in task1 is used as setpoint of a PID (Proporzionale, Integrativo, Derivativo) controller

tte outputtsetpoint tedt

dKdeKteKtu d

t

ip 0

Average Water level Gate opening degree


DSRT 2011, September 4 - 7, Salford, UK 17

SWMM simulation software

DSRT 2011, September 4 - 7, Salford, UK 18

Customizing SWMM

A

A

A

A

A A

A A

A

A

A

A

Real-Time

connector

SWMM

Gossip-Algorithm + PID

Experimental results


Uncontrolled

Controlled

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Any questions?


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