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Embedded system’s design

Powertrain Unit

by Magneti-Marelli

Decomposition of concerns:

Systems and control engineers design controllers

 assuming fast sampling rates for correct operation

Software engineers design real-time operating

 systems and high level code assuming correct Memory 256 Kb

operation of controllers Lines of C code 50 000

6

Productivity Lines/Day

Different teams design different modules that

 Changing rate 3 years

coordinate through digital as well as physical Development 40 man-

communication effort year

Validation time 5 months

The integrated product is then tested and/or verified

 Time to market 24 months

to determine correctness *Fabio Romeo, Magneti-Marelli Design

Automation Conference, Las Vegas,

June 20th, 2001

Correctness is essential in Safety Critical Applications …

 Ariane 5 was launched on 4th June 1996. It exploded 37s after launching due to software error

 The program had been running for 10 years, costing $7 billions

The rocket and its cargo itself cost $500 millions

 The same software worked perfectly on Ariane 4 and it was then used in Ariane 5

What had changed, was the physical system around the software

Power-Train Embedded Controller

• Electronic device controlling an internal combustion

engine and a gearbox

• The goal

– offer appropriate driving performance (e.g. torque,

comfort, safety)

– minimize fuel consumption and emissions

• Relevant characteristics

– strictly coupled with mechanical parts

– hard real-time constraints

– complex algorithms for controlling fuel injection,

spark ignition, throttle position, gear shift …

– Heuristic algorithms and simplistic average-value

models used in the past

Challenges

• Increasing complexity

• New safety, quality and emission requirements

• New System-on-Chip architectures

• Shorter time to market

• NEED more rigorous approach with

– More accurate models

– Clear partition between algorithms and

implementation

– Formal proofs of correctness

– Successive refinement from specifications to

implementation

– Executable Specifications

Engine and Power-train model

Simple?

Throttle Manifold

opening angle (continuous system)

Manifold

pressure Gear

Clutch

Insertion/ change

Engine sub- Release

system

Spark timing Vehicle

Drive-line Speed

Torque (continuous system with

changing dynamics)

Injection Engine and Drive-line



 

Engine and Drive-line

Combustion Process

INTAKE COMPRESSION EXPANSION EXHAUSTED

570°

320°

CRANKSHAFT

ANGLE 120° 440°

FSM for a single cylinder

positive

negative spark

spark advance:

advance:

the spark is given before

after

the TDC between C and E

Single Cylinder Hybrid Model

A glimpse to the future…

• 7000 billions components will serve 7 billions

people in 2017 !!!

(Source: WirelessWorldResearchForum (WWRF))

• 1000 wireless components per person?

[Courtesy: Niko Kiukkonen, Nokia]

ICT Emergent Scenario Infrastructural

core

Sensory

swarm

Mobile

access

Societal Information-Technology Systems

Al di là del dispositivo…

Un insieme complesso di sensori,

controllori, nodi per il calcolo , e

attuatori che collaborano per

migliorare la nostra vita

Triple C convergence

Communication Systems

Control Theory Computer Science

Distributed hybrid

systems


PAGINE

33

PESO

1.08 MB

AUTORE

Atreyu

PUBBLICATO

+1 anno fa


DESCRIZIONE DISPENSA

Embedded Systems:
- computational systems, but not stand alone computers;
- computation interfacing sensors and actuators;
- reactive to physical environment stimuli;
- networked and distributed information processing.


DETTAGLI
Corso di laurea: Corso di laurea magistrale in ingegneria delle telecomunicazioni
SSD:
Università: L'Aquila - Univaq
A.A.: 2011-2012

I contenuti di questa pagina costituiscono rielaborazioni personali del Publisher Atreyu di informazioni apprese con la frequenza delle lezioni di Sistemi embedded e studio autonomo di eventuali libri di riferimento in preparazione dell'esame finale o della tesi. Non devono intendersi come materiale ufficiale dell'università L'Aquila - Univaq o del prof Pomante Luigi.

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