Laboratoire d' Intégration des Systèmes et des Technologies Fabrice AUZANNEAU Embarked diagnosis for wired harnesses of complex topology at CEA LIST

Laboratoire d' Intégration des Systèmes et des Technologies 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 employment in Europe only in this sector. Statistically, electronics alone is responsible for 35% of cars’ failures

Laboratoire d' Intégration des Systèmes et des Technologies Cumulated cable lengths QUEEN MARY 2MODERN CAR CIVIL PLANE km 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

Laboratoire d' Intégration des Systèmes et des Technologies 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

Laboratoire d' Intégration des Systèmes et des Technologies Reflectometry TDR – time domain reflectometry : an active diagnosis method 1.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 accuracy Can detect multiple defects May require complex electronics Ligne de 100 mètres attenuation dispersion DETECTION – LOCALIZATION – CHARACTERIZATION OF DEFECTS

Laboratoire d' Intégration des Systèmes et des Technologies 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 PROVE THE FEASIBILITY OF A HARNESS DIAGNOSIS SYSTEM FOR AUTOMOTIVE APPLICATIONS

Laboratoire d' Intégration des Systèmes et des Technologies FPGA prototyping Signal generation, Injection, Acquisition + Identification et Localization of the defect. Tested and validated first in laboratory conditions.

Laboratoire d' Intégration des Systèmes et des Technologies Tests in real conditions THEN ON REAL HARNESSES IN A CAR

Laboratoire d' Intégration des Systèmes et des Technologies Tests in real conditions PDA – MAN MACHINE INTERFACE SUPPLY CABLES SIGNAL CABLES SIGNAL GENERATION … AND IN A TRUCK

Laboratoire d' Intégration des Systèmes et des Technologies From external to embedded diagnosis EMBARKED DIAGNOSIS EMBARKED DIAGNOSIS DISTRIBUTED DIAGNOSIS ARCHITECTURE SIMPLER SIGNAL PROCESSING NEEDS MUCH LESS COMPUTING 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

Laboratoire d' Intégration des Systèmes et des Technologies 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

Laboratoire d' Intégration des Systèmes et des Technologies SIGNAL GENERATION LINE COUPLINGMODULATION s(t)x(t) SIGNAL EMISSION LINE COUPLINGDEMODULATIONFILTERING x s (t)y(t) SIGNAL DETECTION SIGNAL FORMATTING DATA PROCESSING DATA ANALYSIS DATA PROCESSING DEFECT DETECTION + LOCALIZATION, NETWORK TOPOLOGY Reflectometry principles

Laboratoire d' Intégration des Systèmes et des Technologies 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

Laboratoire d' Intégration des Systèmes et des Technologies Distribution :  Better diagnosis coverage  Reduce data complexity  No more localization ambiguity  More efficient and reliable diagnosis Distributed reflectometry principles Diagnostic Automotive application example

Laboratoire d' Intégration des Systèmes et des Technologies Diagnosis roadmap for automotive applications Diagnosis systems Diagnosis as part of design constraints Cop. ACTIA AUTOMOTIVE Distributed 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

Laboratoire d' Intégration des Systèmes et des Technologies 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

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