Architectures of Automotive Electrical and Electronics (E/E) Systems
Nicolas Navet
Teaching slides
Can be freely used for teaching
Complexity Mastered
Outline
1.
Architecture of Automotive Embedded Systems
ƒ What they look like today – example of BMW and PSA
ƒ Constraints in their design – the case at Volvo
ƒ Need for optimizing resource usage (ECU, networks)
ƒ Possible upcoming architectures
© 2010 N. Navet INRIA / RTaW - 2
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Electronics is the driving force of innovation
–
–
–
90% of new functions use software
Electronics: 40% of total costs
Huge complexity: 70 ECUs,
2500 signals, 6 networks,
multi-layered run-time environment
(AUTOSAR), multi-source software,
multi-core CPUs, etc
Strong costs, safety, reliability, time‐to‐market, reusability, legal constraints !
© 2010 N. Navet INRIA / RTaW - 3
BMW 7 Series networking architecture [10]
ƒ ZGW = central gateway
ƒ 3 CAN buses
ƒ 1 FlexRay Bus
ƒ 1 MOST bus
ƒ Several LIN Buses (not shown here)
ƒ Ethernet is used Eth
ti
d
for uploading code/parameters (End of Line)
Picture from [4]
© 2010 N. Navet INRIA / RTaW - 4
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BMW 7 Series architecture – wiring harness [10]
27Millions
“variants”
Each
wiring
harness is
tailored to
Body, audio,
Body, audio, the
doors, battery, wiring harnesses
options
Picture from [4]
© 2010 N. Navet INRIA / RTaW - 5
There are many non‐technical issues in the design of E/E architecture The case at Volvo in [2] :
Architectural decisions often:
– Influence of E/E architecture wrt to business value?
9 lack well‐accepted process
lacks long
g term strategy
gy
9 are made on experience / – Lack of background in E/E at management level
gut feeling (poor tool often mechanical background
support)
– Lack of clear strategy between in-house and
externalized developments
– Technical parameters are regarded as less
important than cost for supplier / components selection
– Vehicle Family Management : How to share architecture
and sub-systems between several brands/models
with different constraints/objectives?
– Sub-optimal solutions for each component / function
– Legal / regulatory constraints
© 2010 N. Navet INRIA / RTaW - 6
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Proliferation of ECUs raises problems!
Number of ECUs (CA
AN/MOST/LIN)
50
45
40
35
30
25
20
Mercedes-Benz
BMW
Audi
VW
15
10
5
0
1986
1988
1990
1992
1994
1996
1998
2000
Year
2002
2004
2006
2008
Pictures from [3]
Lexus LS430 has more than 100 ECUs [wardsauto]
© 2010 N. Navet INRIA / RTaW - 7
The case of a “generalist” car manufacturer ‐ PSA 45
40
35
CAN LAS
info-div
LIN
CAN CAR
CAN CONF
CAN I/S
30
25
20
15
10
5
0
X4-2000
X4-2003
D2 2004
D2 TG
D25
PF3
X3
X6-2005
X7-2007
W2
Pictures from [6]
The number of ECUs has more than doubled in 10 years
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Optimizing the use of networks is becoming an industrial requirement too
Good reasons for optimizing :
–
–
–
–
–
Complexity of the architectures (protocols, wiring, ECUs, gateways, etc )
Hardware cost,
cost weight,
weight room,
room fuel consumption,
consumption etc
Need for incremental design
Industrial risk and time to master new technologies (e.g. FlexRay)
Performances (sometimes):
– a 60% loaded CAN network may be more efficient that two 30%
networks interconnected by a gateway
– Some signals must be transmitted on several networks
from [7]
© 2010 N. Navet INRIA / RTaW - 9
Likely upcoming architectures
Fewer ECUs but more powerful
–
–
–
–
–
Multi-core μ-controller
Multi-source software
Autosar OS strong protection mechanisms
Virtualization ?
ISO2626-2 dependability standard
FlexRay
as backbone
as backbone at BWM in a few years [7]
Backbone:
‐ High‐speed CAN : 500Kbit/s
‐ FlexRay : 10 Mbit/s
Fl R
10 Mbit/
‐ Ethernet ?
Picture from [7]
© 2010 N. Navet INRIA / RTaW - 10
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Conclusion
„
„
„
Today’s automotive E/E architectures are very complex, partly due to carry‐over
It may require one or two car generations to see major changes toward simplified architectures with fewer ECUs, high‐speed communication backbones, etc
Dependability creates new needs:
Dependability creates new needs:
„
„
Increasing safety‐related functions (X‐by‐Wire)
Certification in the context of ISO26262 © 2010 N. Navet INRIA / RTaW - 11
References
© 2010 N. Navet INRIA / RTaW - 12
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References
Automotive Embedded Systems
[1] N. Navet, F. Simonot‐Lion, editors, The Automotive Embedded Systems Handbook, Industrial Information Technology series, CRC Press / Taylor and Francis, ISBN 978‐0849380266, December 2008.
[2] P. Wallin, Axelsson, A Case Study of Issues Related to Automotive E/E System Architecture Development, IEEE International Conference and Workshop on the Engineering of Computer Based Systems, 2008.
[3] T. Nolte, Hierarchical Scheduling of Complex Embedded Real‐Time Systems, Summer School on Real‐Time Systems (ETR’09), Paris, 2009.
[4] H. Kellerman, G. Nemeth, J. Kostelezky, K. Barbehön, F. El‐Dwaik, L. Hochmuth, “BMW 7 Series architecture”, ATZextra, November 2008. [5] N. Navet, “In‐Vehicle Networking : a Survey and Look Forward”, Workshop on Specialized Networks, in conjunction with IEEE ETFA 2009, Mallorca, Spain, September 26, 2009. Available at http://www.realtimeatwork.com
[6] N. Navet, B. Delord, M. Baumeister, “Virtualization in Automotive Embedded Systems : an Outlook”, talk at RTS Embedded Systems 2010, Paris, France, March, 2010. Available at http://www.realtimeatwork.com
[7] A. Schedl, “Goals and Architecture of FlexRay at BMW”, slides presented at the Vector FlexRay Symposium, March 2007. © 2010 N. Navet INRIA / RTaW - 13
Questions / feedback ? Please get in touch at:
nicolas.navet@inria.fr
© 2010 N. Navet INRIA / RTaW - 14
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