The document discusses architectural simulation as a method for validating distributed automotive systems. It defines architectural simulation and related terms, then presents a taxonomy for classifying model abstraction. The document also examines dependencies between abstraction levels and model types. As an example, it applies architectural simulation to a brake-by-wire system, showing scheduling analyses and results. Advantages are better test coverage and depth than other methods, though disadvantages include effort required and limited accuracy.

1. Motivation Definition Abstraction Classification Sample Usage Summary
Architectural Simulation of
Distributed ECU Systems
Joachim Schlosser
16. Dezember 2005

2. Motivation Definition Abstraction Classification Sample Usage Summary
Why Architectural Simulation?
Context & Motivation
Increasing complexity of automotive systems
Highly interconnected controller and control loop systems
Complicated integration of functions
) Support the development of the technical architecture:
Flexible validation
earlier, well­founded
assertions on temporal and functional
behavior
Recognize HW/SW integration issues earlier
Task of the thesis: define, classify, assess

3. Motivation Definition Abstraction Classification Sample Usage Summary
Terms of Architectural Simulation
Architectural simulation:
execute behavioral models +
architecture effects
(Technical) architecture:
hardware platform + system platform
Behavioral model:
functional behavior of components
) Architectural simulation is a test method.
) Architectural simulation serves validation.

4. Motivation Definition Abstraction Classification Sample Usage Summary
Related Work
Functional simulation, e. g. Matlab/Simulink, ASCET­SD
Rapid prototyping, e. g. xPC, dSpace, ETAS
Hardware simulation, e. g. VHDL, Verilog
Static architecture analysis, e. g. function chains, WCET
analysis, scheduling analysis

5. Motivation Definition Abstraction Classification Sample Usage Summary
Principle
Principle of Architectural Simulation
Example: safety critical, redundant system
fA Signal1
fB Signal2
fC
Verhalten
Architektur
ECU1
Mem
OSEK
CPU
BusCtrl BusCtrl BusCtrl
ECU2
Mem
OSEK
CPU
BusCtrl BusCtrl BusCtrl
BusA
BusB
BusC

6. Motivation Definition Abstraction Classification Sample Usage Summary
Reflection of Abstraction
Why a Taxonomy?
Discussions on abstraction dissatisfying
Solution: use abstraction taxonomy
) Improve discussion
) Ensure consistency of models
) Detect model disharmony and put in metric
) Benchmark modeling and simulation tools

7. Motivation Definition Abstraction Classification Sample Usage Summary
VSI Taxonomy
Virtual Socket Interface Alliance: System Level Model Taxonomy
Time 1
Gate
accurate
2
Cycle
accurate
3
Cycle
approx.
4
Instruction
cycles
5
Data
cycles
6
System
events
7
Partial
order
Data 1
Bit
2
Data type
3
Abstract type
4
Property
5
Token
Function 1
Digital logic
2
Implementation
3
Algorithm
4
Mathematical
Structure 1
Structure
2
Block diagram
3
Black box
Program 1
Object code
2
Mikro code
3
Assembler
4
High level
language
5
DSP
primitive
6
State
machine

8. Motivation Definition Abstraction Classification Sample Usage Summary
Notation
Simplification
VSI Taxonomy, displayed as vector:
a =
aZ
aD
aF
aS
aP
! Time
Data
Function
Structure
ProgrammingModel
!
disuse of axis expressed by ?
abstraction ranges written as intervalls, e. g.
aV =
0
@
[4;7]
[2;4]
22?
1
A

9. Motivation Definition Abstraction Classification Sample Usage Summary
Dependencies betweeen Abstraction Axes
Correlations
Abstraction axes are not orthogonal.
ProgrammingModel
Time
Structure
Data Function
Why important?
Consistency of models (‘model harmony’)

10. Motivation Definition Abstraction Classification Sample Usage Summary
Dependencies betweeen Abstraction Axes
Sample Relation, Sample Usage
Sample: RZP = Time ProgrammingModel
Time 1 2 3 4 5 6 7
Program 2 2 3 3 4 5 6
Sample usage:
CPU modell for run time estimation
Estimates generated C code (level P = [4; 6])
To deliver instruction cycles (level Z = 4)
Relation states: RZP(4) = 3
) Model cannot meet requirements

11. Motivation Definition Abstraction Classification Sample Usage Summary
Dependencies between Types of Models
Why?
Harmony of interacting models
Discrepancy of abstraction admissible according to
individual dependency
Consistency of abstraction of whole system

12. Motivation Definition Abstraction Classification Sample Usage Summary
Types of Models with Abstraction and Dependencies
Funktionsnetzstruktur
Komponentenverhalten Komponentenimplementierung
1
Betriebssystem
Middleware
Stimulation Simulation
Architektur
Prozessor
Abbildung
Verhalten
Nachricht
Speicher
Signal
Prozess Task
Feldbus
Analyse
Fehler
1
1..*
1
1..*
1..* 0..1
0..*
1..*
1..*
1
1..* 0..1
0..1
1..* 1 1
1
1
0..1
1..*
0..1
1..*
0..1
0..*
0..*
1
1..*

13. Motivation Definition Abstraction Classification Sample Usage Summary
Types of Models with Abstraction and Dependencies
1
CA
Betriebssystem
Prozessor
Nachricht
1
1
0..1
0..1
0
B@
1
[2;5]
2
[2;3]
3
[1;4]
CA
0
B@
[4;6]
[2;4]
33 [1;5]
0
@
1
A
22112

14. Motivation Definition Abstraction Classification Sample Usage Summary
Types of Models with Abstraction and Dependencies
P0ostulation:
@
1
A
[4;6]
[2;4]
33
[1;5]
22112
+
0
@
1
A
[2;5]
2
[2;3]
3
[1;4]

15. Motivation Definition Abstraction Classification Sample Usage Summary
Architectural Simulation in the Development Process
(extremely simplified, no iterations)

16. Motivation Definition Abstraction Classification Sample Usage Summary
Example of Usage Brake­by­Wire
Simulation and architecture modeling with
Cadence VCC/SysDesign
Function modeling with ETAS ASCET­SD
Sensor vRL
Bremsaktor RL
Sensor vRR
Sensor vFL
Bremsaktor FL
Sensor vFR
Bremsaktor RR
Bremsaktor FR
Bremspedal
Sensor
Feststellbremse
Schalter

17. Motivation Definition Abstraction Classification Sample Usage Summary
Simulation Results
Scheduling 1
0,10
0,08
Gesamtlatenz 43,5ms
20ms 10,6ms
u u Task (a) q Pedalpos. Sens. MCU2
0,06
(b) r Pedalpos. Sens. MCU2 auf MCU2
(c) + Pedalpos. Sens. MCU2 auf MCU1
(d) u normalisierte Klemmenkraft fl lokal
(e)
0,04
r r r 0,02
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
+ +
r
r
q q q q + + +
u r q u r q
u r
u u
0
3,500 3,505 3,510 3,515 3,520 3,525 3,530 3,535 3,540 3,545
3.50 3.51 3.52 3.53 3.54
Arch/MCU1
Arch/MCU2
Arch/MCU3
Arch/WCU_FL
Arch/WCU_FR
Arch/WCU_RL
Arch/WCU_RR
MCU1 OSEK::Archi...
Behav/Fehlerbeh.
Behav/Kraft_rl
Behav/Kraft_fr
Behav/Überwachung
Behav/Sensorsignal
Behav/Kraft_rr
Behav/Signalverarb.
Behav/Kraft_fl
Behav/Längskraft
0 1 2 3 4 5 6 7
bus
allocation
(
prozessor
utilization
(
r
normalisierte Klemmenkraft fl MCU2 aufWCU fl

18. Motivation Definition Abstraction Classification Sample Usage Summary
Simulation Results
Scheduling 2
0,10
0,08
Gesamtlatenz 21,0ms
4,5ms 4,3ms
u u u 0,06
Task r
r
r
r
r
r
r
r
r
r
r
0,04
r r r r 0,02
r
r u r
r
q r
r
r u r
r
q
r
r
r
u
r
r
r
r
r
0
+ + +
q q q q +
3,500 3,505 3,510 3,515 3,520 3,525 3,530 3,535 3,540 3,545
3.50 3.51 3.52 3.53 3.54
Arch/MCU1
Arch/MCU2
Arch/MCU3
Arch/WCU_FL
Arch/WCU_FR
Arch/WCU_RL
Arch/WCU_RR
MCU1 OSEK::Arch...
Behav/Fehlerbeh.
Behav/Kraft_rl
Behav/Kraft_fr
Behav/Überwachung
Behav/Sensorsignal
Behav/Kraft_rr
Behav/Signalverarb.
Behav/Kraft_fl
Behav/Längskraft
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8

19. Motivation Definition Abstraction Classification Sample Usage Summary
Advantages of Architectural Simulation
Comparison to other test methods
Better test depth
some properties hard or impossible to reproduce with real
hardware
Better test coverage
automated tests, simulation computers easier scale better
than HiL/RP systems

20. Motivation Definition Abstraction Classification Sample Usage Summary
Disadvantages
Problem of test coverage
In early phases no detailed models
) limited simulation accuracy
Limited accuracy of software run time estimation
Effort for assembly, analysis, model adation
Complexity of tool chain and models

21. Motivation Definition Abstraction Classification Sample Usage Summary
Summary and Perspective
Architectural Simulation
Architectural simulation defined, classified, benchmarked
Metrics for abstraction review
) Earlier disclosure of inconsistencies in design and
implementation
) Project dependent balancing of effort to expected benefit
) Architectural simulation as project stopped
) Use of static architecture analysis instead of/ ahead of
architectural simulation