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Tesi etd-06302016-105218


Thesis type
Tesi di laurea magistrale
Author
PAZZAGLIA, PAOLO
URN
etd-06302016-105218
Title
Analysis of the Impact of Real-Time Scheduling on Engine Control Performance
Struttura
INGEGNERIA DELL'INFORMAZIONE
Corso di studi
INGEGNERIA ROBOTICA E DELL'AUTOMAZIONE
Commissione
relatore Prof. Buttazzo, Giorgio C.
correlatore Prof. Di Natale, Marco
correlatore Biondi, Alessandro
Parole chiave
  • Real Time
  • Engine Control
  • AVR
  • Scheduling
Data inizio appello
21/07/2016;
Consultabilità
parziale
Data di rilascio
21/07/2019
Riassunto analitico
The modern Engine Control Unit (or ECU) has become a complex and powerful
electronic device, being able to manage all fundamental aspects of passenger cars.
A typical ECU is characterized by computational activities that are periodic or
triggered by the rotation of the crankshaft, thus generating a workload variable
with the engine speed. To prevent overloads, a common practice with angular
tasks is having a certain number of operational modes implemented, with different
computational cost, that are activated at different speed intervals: for that reason
they are also referred as Adaptive Variable Rate (AVR) tasks. Understanding
how different choices of switching speeds and computational loads influence the
behaviour of the engine is fundamental to obtain the best performances of the
system.
This thesis presents a mathematical model of a Diesel engine, created in Simulink
environment, that is used to test the impact of Real-Time scheduling on a set of
performance indices (thermodynamic efficiency, pollutant emission, noise). First,
the schedulability problem for AVR task sets is presented, with the theoretical
basis and state of the art. The mathematical model is then illustrated in detail:
the dynamic of the engine is modelled using a simplified set of physical equations
taken from specialized literature, while the controller is inspired by the real ECU
using a mix of maps and robust control laws. The scheduler is integrated in the
Simulink model using the T-Res framework (a RTSim Simulink interface), which
has been modified to manage also the AVR tasks in its features. Finally, a series
of tests are made, varying the switching speeds and control strategies, to show
how performance indices are influenced. An experimental validation of the model
is also presented to demonstrate the applicability of these results.
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