laboratoire d' intégration des systèmes et des technologies fabrice auzanneau...

Laboratoire d' Intégration des Systèmes et des Technologies

Fabrice [email protected]

01 69 08 90 70

Embarked diagnosis for wired harnesses of

complex topology at CEA LIST


Electronics in transports

Electronics in a modern car is more expensive than the steel used to make it, and top-of-the-range models can contain more than 100 CPUs. Most of the innovations in current cars come from electronics. Electronics currently represents nearly 25% of the cost of a vehicle, and this will double before 2010, involving the creation of more than 600.000 employment in Europe only in this sector.

Statistically, electronics alone is responsible for 35% of cars’ failures


Cumulated cable lengths

QUEEN MARY 2MODERN CAR CIVIL PLANE

km

101 1000100 100004

40 200 1200

2500400

BUS

HELICOPTER

FPSO (Floating Production, Storage and Offloading unit)

MODERN FIGHTER HIGH SPEED TRAIN

1km / m

5 km / m

8 km / m

A CABLE DEFECT IS OFTEN MISTAKEN TO BE AN ELECTRONIC DEFECT


Reliability and harness diagnosis

Diagnosis systems already exist in modern cars for ECUs (Built-in test systems) – ECU health monitoring

– Sometimes, they provide information on the communication bus health

Today there exists no such diagnosis system for the cable harness– The harness is a system on its own information transfer, energy supply

– Maintenance can be very hard• Today, a mechanic can spend 2 days to isolate and repair a cable defect,

sometimes after having changed healthy and costly equipments…

– Harness maintenance is expensive : immobilization time + defect search time

70% of ECU returned to manufacturers are diagnosed free from defects

There is a real need for a tool able to tell if the harness is healthy and precisely locate a defect


Reflectometry

TDR – time domain reflectometry : an active diagnosis method1. Sending a probe signal down the network 2. During its propagation, part of its energy is

reflected back by electrical discontinuities (defects, branches, loads…)

3. Reflected signal analysis provides information about the network’s health

High localization accuracy (few % of the length)– But dispersion, attenuation, sampling,

digitization can alter accuracyCan detect multiple defectsMay require complex electronics

Ligne de 100 mètres

attenuation

dispersion

DETECTION – LOCALIZATION – CHARACTERIZATION OF DEFECTS


The SEEDS project

Financed by ANR, the SEEDS project aims at proving the feasibility of a harness diagnosis system for automotive applications– Smart Embedded Electronic Diagnosis System

7 partners : the complete chain from upstream research to end-user, via technology providers– CEA LIST, INRIA, SUPELEC LGEP– DELPHI, RENAULT TRUCKS, SERMA, MONDITECH

Objectives :

– Understand and model the physics of RF signals propagation in automotive / trucks harness cables

– Identify and simulate a diagnosis method for cables and connectors – Study, design and prototype a harness diagnosis system for road

vehicles

2006 2009

PROVE THE FEASIBILITY OF A HARNESS DIAGNOSIS SYSTEM FOR AUTOMOTIVE APPLICATIONS


FPGA prototyping

Signal generation, Injection, Acquisition + Identification et Localization of the defect.

Tested and validated first in laboratory conditions.


Tests in real conditions

TH

EN

ON

RE

AL

HA

RN

ES

SE

S I

N A

CA

R


Tests in real conditions

PDA – MAN MACHINE INTERFACE

SUPPLY CABLES SIGNAL CABLES

SIGNAL GENERATION

… A

ND

IN

A T

RU

CK


From external to embedded diagnosis

EMBARKED DIAGNOSISEMBARKED DIAGNOSIS

DISTRIBUTED DIAGNOSIS DISTRIBUTED DIAGNOSIS ARCHITECTUREARCHITECTURE

SIMPLER SIGNAL PROCESSING

NEEDS MUCH LESS NEEDS MUCH LESS COMPUTING POWERCOMPUTING POWER

OBJECTIVE :DIAGNOSIS

INTEGRATION

SIMPLE NETWORK TOPOLOGY

DIAGNO CHIP

ADDITIONAL STRUCTURES TO

SIMPLIFY FURTHER

EXTERNAL DIAGNOSIS

COMPLEX NETWORK TOPOLOGY

COMPLEX SIGNAL PROCESSING

CAN RUN ON A PC

NEEDS COMPUTING POWER


Embedded harness diagnosis

Operational constraints– The diagnosis must not interfere with the system

– Diagnosis architecture must be considered– Diagnosis strategy

• Improve localization accuracy a few centimeters

– Microelectronic integration

Compliance to standards– EMC, etc

Cost– As close as possible to … zero

Embedding harness diagnosis inside the vehicle requires new paradigms

A new diagnosis method is required


SIGNAL GENERATION

LINE COUPLINGMODULATION

s(t) x(t)

SIGNAL EMISSION

LINE COUPLINGDEMODULATIONFILTERING

xs(t)y(t)SIGNAL DETECTION

SIGNAL FORMATTING

DATA PROCESSING

DATA ANALYSIS

DATA PROCESSING

DEFECTDETECTION +

LOCALIZATION,NETWORK TOPOLOGY

Reflectometry principles


S T

A new method : STDR principles

From the processing and analysis of time domain signals, one can deduce the localization and type of the defect.

Binary pseudo noise sequence with sharp auto-correlation peak

The signal propagates along the line and comes back time-shifted

by two times the defect’s distance

Defect Probe signal

Reflected signal


Distribution : Better diagnosis coverage Reduce data complexity No more localization ambiguity More efficient and reliable diagnosis

Distributed reflectometry principles

DiagnosticD

iag

no

stic

TRAITEMENT

GÉNÉRATION ACQUISITION

Diagnostic filaire

Flexray

ECUengine

µP

Mem

ory

SoC

Asic1

Asic2

Glue

Glue

µC

Mem

ory

IPCore2

Glue

IPCore1

CAN

Body control module

CAN

Driver doormodule

CAN

Airbag

CAN

Passenger door module

Flexray

Yaw rate sensor

Flexray

Electronic stability program

Flexray

Electro-hydraulic

powersteering

Flexray

Automatic headlamp

control

Flexray

Automatic transmission

control

CAN

Underhoodelectronics

CAN

Instrument panel cluster

CAN

Rear electronics

central module

CAN

Parking assistant

CAN

Displays

CAN

Auxiliaryheater

CAN

Sun roof module

CAN

Interface

Flexray

Flexray

ECUengine

µP

Mem

ory

SoC

Asic1

Asic2

Glue

Glue

µC

Mem

ory

IPCore2

Glue

IPCore1

CAN

Body control module

CAN

Driver doormodule

CAN

Airbag

CAN

Passenger door module

Flexray

Yaw rate sensor

Flexray

Electronic stability program

Flexray

Electro-hydraulic

powersteering

Flexray

Automatic headlamp

control

Flexray

Automatic transmission

control

CAN

Underhoodelectronics

CAN

Instrument panel cluster

CAN

Rear electronics

central module

CAN

Parking assistant

CAN

Displays

CAN

Auxiliaryheater

CAN

Sun roof module

CAN

Interface

Flexray

Automotive application example


Diagnosis roadmap for automotive applications

2004 2006 2008 2010 2012

Dia

gn

osi

s sy

stem

s

Diagnosis as part of design

constraints

Cop. ACTIA

AUTOMOTIVEDistributed diagnosis

(multiplexing)

External diagnosis systems

Wired network

diagnosis

CALCULATORS

ENTIRE NETWORK

ENTIRE NETWORK, DISTRIBUTED DIAG.

ENTIRE NETWORK, INTEGRATED DISTRIBUTED DIAG.

Systems are dynamically

diagnosed and reconfigured


Conclusions and perspectives

The feasibility of an external harness diagnosis system is proven – its interest was demonstrated for garage application

Validation in real life conditions has shown its robustness. – Robustness to parasitic signals (CAN bus validation) and to test

cases variations

Embedding the diagnosis system in the vehicle is currently under study– Active fault tolerance “Smart Interconnect”

Numerous other application domains are identified – transports, energy, telecommunication, infrastructures and building…– Generic technologies and upstream research will be transferred


THANK YOU FOR YOUR ATTENTION

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