Ulf Andersson nr1.ps

230 Pages·2013·33.95 MB·English

ISSN: 1402-1544 ISBN 978-91-7439-XXX-X Se i listan och fyll i siffror där kryssen är
DOCTORA L T H E S IS
Department of Computer Science, Electrical and Space Engineering
Division of Systems and Interaction
U Automation and Traction Control
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ISSN: 1402-1544 A
ISBN 978-91-7439-801-4 (print) n of Articulated Vehicles
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Automation and Traction Control
of Articulated Vehicles
Ulf Andersson
Luleå University of Technology
Department of Computer Science, Electrical and Space Engineering
Division of Systems and Interaction
Printed by Luleå University of Technology, Graphic Production 2013
ISSN: 1402-1544
ISBN 978-91-7439-801-4 (print)
ISBN 978-91-7439-802-1 (pdf)
Luleå 2013
www.ltu.se
To my family

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BSTRACT
Articulated machines such as load-haul-dump machines, wheel loaders and haulers operate
in many different environments and driving conditions. In particular they need to be able to
perform well with road conditions and loads that can change drastically, setting hard
requirements on performances and robustness. The control challenges for off-road vehicles
are hence quite different from standard cars or trucks, which mostly drive on regular roads.
An important aspect characterising this is the fact that wheel slip may cause severe damage
to the wheels and ground. Particularly, tyre lifespan is a serious problem since for instance
in a modern hauler the tyres often represents 20%-25% of a hauler overall operating cost.
Better traction control algorithms can strongly contribute to reducing tyre wear and hence
operating costs.
Increasing fuel prices and increasing environmental awareness have influenced all the main
vehicle manufacturers so that the commitment towards less fuel consumption has become
one of the main goals for development. During the last few years’ hybrid vehicles have
been vigorously developed. For wheel loaders, in particular, the series hybrid concept seems
to be suitable whereby a diesel engine generates electricity for a battery that serves as the
power source of the individual wheel motors, enabling regenerative braking as well as
partial recovery of the energy necessary to lift the load. Hence, traction control algorithms
should be adapted for use with individual wheel drives.
Load-haul-dump machines, wheel loaders and haulers are sometimes used in cyclic
operations in isolated areas, which is a typical driver for automation. The use of the load-
haul-dump machine in underground hard rock mines such as iron ore mines is one example
where the conditions for automation are excellent. The working conditions for a driver in the
cabin are monotone. The working conditions are improved by moving the driver from the
machine to a control room and alternate between different remote operations, for instance
between load-haul-dump machines and remote controlled rock breaker. Moving the driver
from the cabin to the control room also have a positive effect on the personnel costs since
one operator can handle several machines.
However, for the automation to be successful, the cycle time and loading capacity of an
automated machine has to match a manual machine operated by skilled drivers. A challenge
is the remote bucket filling, where traditional tele remote loading is based only on slightly
delayed video feedback from the machine. This is in sharp contrast to the manual loading
where the driver close the loop based on non-delayed 3D vision of the machine relative the
pile as well as listening to the noise and sensing the vibrations of the machine.

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HESIS NTRODUCTION
The author of this thesis was a PhD student from 1986 to 1989 at Luleå University of
Technology, working in a research project that developed a laser based navigation system
for automatic guided vehicles (AGVs). The project resulted in a spinoff company,
AutoNavigator AB, with the goal to commercialise the laser navigation system, two
licentiate theses - Wiklund (1988) and Andersson (1989) - and one doctoral thesis Hyyppä
(1993).
The laser navigation system was adapted to automation of the load-haul-dump (LHD)
vehicles at the LKAB Kiruna iron ore mine in Sweden in 1996 and used in production from
1999 to 2009. LHD automation is the subject of the first part of the thesis.
The second part of the thesis deals with traction control for articulated vehicles. The need
for traction control became clear during the production period. Wheel spin during remote
controlled loading of fragmented rock had a negative impact on the production.
Volvo Construction Equipment initiated 2009 a VINNOVA research project with focus on
traction control for off-road construction vehicles at Luleå University of Technology in
which the author re-started the work as a PhD student. The first part of the traction control
project finished in mid 2013. VINNOVA has granted a two-year extension of the project
with focus on traction control for construction vehicles propelled by individual wheel drives.
Work in the second part of the traction control project is not part of the thesis.
The common factor for both parts of the thesis is the articulated vehicle. An introduction to
this type of vehicle is found in chapter 1. Readers familiar with the articulated vehicle can
skip this part of the thesis.
The history of the laser navigation system since the founding of AutoNavigator AB up until
today is discussed in Andersson (2013) with focus on commercialisation aspects.
References
Andersson, U. (2013). Laser navigation system for automatic guided vehicles – From
research project to commercial product, Research Report, Luleå University of
Technology, Luleå, Sweden.
Andersson, U. (1989). Trajectory estimation and control of autonomous guided vehicles,
Licentiate Thesis, Luleå University of Technology, Luleå, Sweden.
Hyyppä, K. (1993). On a laser anglemeter for mobile robot navigation, Doctoral thesis,
Luleå University of Technology, Luleå, Sweden.
Wiklund, U. (1988). Algorithms for navigation of autonomous guided vehicles, Licentiate
Thesis, Luleå University of Technology, Luleå, Sweden.
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