Sébastien Cabaret - October 20071

From regulation basics to advanced control

Sébastien Cabaret - October 20072

Overview

Regulation: what is a control loop? What is a PID controller? What is advanced control? Identifying, Modeling …. Tuning Advanced control example: predictive control Schneider tool for Modeling and Tuning

available in ITCO Application for GCS: MultiController

Sébastien Cabaret - October 20073

Regulation: what is a control loop?

“I want to see a measured value which corresponds to my request”

Sébastien Cabaret - October 20074

Regulation: what is a control loop?

Reaction:The water temperature reacts

on heating power changesTemperature

SensorTE

Controller or human!

Acts on heating power (4-20mA)

(0-500W)

DesiredTemperature

(ex: 150C)

Sébastien Cabaret - October 20075

Regulation: what is a control loop?

Control Loop system Representation Example: Open Loop representation

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Regulation: what is a control loop?

Control Loop system Representation Example: Closed Loop representation

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Reaction:The water temperature reacts

on heating power changesTemperature

Sensor (y)TE

C(p)Acts on heating power

(u, 4-20mA)

Desired Temperature(SP, 150C)

G(p)

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What is a PID controller?

PID means Proportional, Derivative Integrative. In a classic control loop system, the PID is the controller placed

before the process:

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What is a PID controller?

PID Elementary actions Proportional

KpCP )(

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What is a PID controller?

PID Elementary actions Integrative

Ti is the coefficient given to increase or decrease the integrative action

pTpC

iI .

1)(

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What is a PID controller?

PID Elementary actions Derivative

Td is the coefficient given to increase or decrease the derivative action

pTpC dD .)(

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What is a PID controller?

PID Elementary actions Sum up

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What is advanced control?

Advanced Control - Sébastien Cabaret – 9 Feb. 2006

Basic corrections PID

Other strategies

Advanced strategies

GPC, PFC, RST, IMC…

OthersFuzzy, Neuronal

network, …

Need for process identification

System complexity

Advanced Control

Sébastien Cabaret - October 200714

Identifying, Modeling… Tuning

Process to tune a controller We should have the knowledge of the system We should give information to the controller for its tuning

System information

Controller parametersTUNING

Ex: P,I and D for PID

Data acquisition Identification Modeling

Methods

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Advanced control example: predictive control

The predictive control method is an advanced control strategy It is a good compromise between performance and

complexity It is based on a model for the prediction of the process

output and on a determinate horizon It also uses a reference trajectory to attempt the desire

response

Several predictive controls exist due to various mathematical approaches of automation people.

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The predictive control is closed to human driver behavior

The controller contains the model of the process to drive

The model allows to predict the effect of the action to the system output

The driver has built a «mental picture» of its car behaviors

He knows the efficiency of the brakes and knows the effect to his car

A process model is integrated into the controller

SetPoint

The controller has the system knowledge and is able to calculate future action to have a desire output behavior

Action

ProcessOutput

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The model used by the controller is a dynamic representation of the input/output relationships (ex: mental model of the car vs. the road)

The reference trajectory is known by the controller (ex: car trajectory)

The horizon definition is specified (ex: 20 seconds)

Predictive Control

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Model

Reference trajectory

Real trajectory

Horizon

Set Point

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Future

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Schneider tool for Modeling and Tuning available in ITCO

Optireg

•Schneider PLC •Some predictive algorithms

•PID

DataStore

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Application: MultiController object in GCS project

EN

TR

Ramp

LimHSPLimLSP

MRegSel

Scaling

FromOutO

ManReg01

AuAuMoRMPosVal

MPTSel

IoSimu

MPRSel

RA

MPBSel

AuSPo

TRVal

AuRegR

MSPo

MPTime

IoError

RCPY

Param

AuRegSel

AuPosVal

LimLO

MV

LimHO

MPReal

EnRcpy

ENO

IoSimuW

LimHSPStLimLSPSt

StsReg01

AuPosVSt

FoMoStRegSt

MVSt

IoErrorW

AuMoSt

RegSelSt

TRSt

ScalingSt

AuSPoSt

OutOD

ParamSt

SPoSt

MMoSt

LimLOSt

OutO

LimHOSt

PosValSt

FBI_1

MultiControl ler14

Sébastien Cabaret - October 200722

Application: MultiController object in GCS project

TR

Ramp

LimHSPLimLSP

MRegSel

Scaling

FromOutO

ManReg01

AuAuMoRMPosVal

MPTSel

IoSimu

MPRSel

RA

MPBSel

AuSPo

TRVal

AuRegR

MSPo

MPTime

IoError

RCPY

Param

AuRegSel

AuPosVal

LimLO

MV

LimHO

MPReal

EnRcpy

IoSimuW

LimHSPStLimLSPSt

StsReg01

AuPosVSt

FoMoStRegSt

MVSt

IoErrorW

AuMoSt

RegSelSt

TRSt

Scal ingSt

AuSPoSt

OutOD

ParamSt

SPoSt

MMoSt

LimLOSt

OutO

LimHOSt

PosValSt

FBI_0

MultiController1

s0

s2

t1t2

r2

t6

r5

s3

s5

s10

r4

s8

start

s11

SetPoint

s1

r1

s6

s4

r3

t0

t5

r0

r6

t4

s9

MV

t3

s7

Output

FBI_1

RST_sc2

Ny

Tref

start

d

Te

MV

H

SetPointOUT

Kraidzbh

FBI_2

PFCgene_sc3

LimLSetPoint

RangeHSetPoint

Time_constant

LimLOutput

RangeLSetPoint

Tr

LimHOutput

SetPoint

ReverseAction

Order

Delay

PI_RA

Gain

Instable

LimHSetPoint

MV

Start

Output

FBI_4

SmithPredictor_sc6

INITPVSPRCPYIMPTUNELIMMANYMAN

YIMVERR

FBI_6

SF1_V24

INITPVSPRCPYIMPTUNELIMMANYMAN

YIMV

ERREUR

FBI_5

DC3_V25

INITPVSPRCPYIMPTUNELIMDECOMPMANYMAN

YIMVERR

FBI_3

IF1_V27

PVSPFFRCPYMAN_AUTOPARATR_ITR_SOUT OUT

STATUS

MA_O

OUTD

INFO

FBI_7

PIDFF8

The MultiController is a standard UNICOS object for Schneider PLC and PVSS SCADA system

Replace UNICOS PID controller UNICOS compatible (modes,

connection, hierarchy) It has a single interface for all

regulation algorithms The design allows the addition of

new control loop algorithms without changing the object interface

It has been design to offer a recipe mechanism. It allows the process expert to keep and reuse pertinent sets of tuning parameters

IF1

PIDMultiController

RST

DC3 SF1

PFC generalized

Smith Predictor

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Application: MultiController object in GCS project

The MultiController is a standard UNICOS object for Schneider PLC and PVSS SCADA system

It has a unique Human Machine Interface with different views

It is composed of a synoptic, trend views, navigation buttons

It allows a global control of the regulation loop via a centralized object representation in the HMI with different views

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MultiController operation under PVSS

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MultiController future application: adaptive control

System to control

Online ModelIdentification under PLC

u

y

Model representation:Ex: first order in discrete approach

B1.z-1

H(z)= 1+A1.z-1

GPC tuningMechanism in PLC(Predictive strategy)

A1, B1

GPCParameters

Set Point

EN

TR

Ramp

LimHSPLimLSP

MRegSel

Scaling

FromOutO

ManReg01

AuAuMoRMPosVal

MPTSel

IoSimu

MPRSel

RA

MPBSel

AuSPo

TRVal

AuRegR

MSPo

MPTime

IoError

RCPY

Param

AuRegSel

AuPosVal

LimLO

MV

LimHO

MPReal

EnRcpy

ENO

IoSimuW

LimHSPStLimLSPSt

StsReg01

AuPosVSt

FoMoStRegSt

MVSt

IoErrorW

AuMoSt

RegSelSt

TRSt

ScalingSt

AuSPoSt

OutOD

ParamSt

SPoSt

MMoSt

LimLOSt

OutO

LimHOSt

PosValSt

FBI_1

MultiController14

MultiController

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Advanced Control

Questions