A STUDY ON LATERAL CONTROL OF
AUTOMATIC HEAVY-DUTY VEHICLES
Wei Liang *, Jure Medanic **, Roland Ruhl ***
* Dept. of Mechanical and Industrial Engineering
University of Illinois at Urbana-Champaign
Email: weiliang@uiuc.edu
** Dept. of General Engineering and Coordinated Science Lab
University of Illinois at U-C, Email: jmedanic@uiuc.edu
Urbana, Illinois USA 61801
*** Ruhl Forensic Co. and University of Illinois
Champaign, IL 61820 Email: rruhl@ruhl.com
Abstract: Intelligent Platoon of Heavy Duty Vehicles (IPHV) is a commercially attractive
application of ITS. The control of articulated truck, however, poses problems not
encountered with two-axle passenger vehicles. In case of autonomous implementation
of the controller the lateral control problem reduces to a specific tracking problem that
relies only on relative distance and velocity measurements. The nature of this tracking
problem, is analyzed using a linearized model of lateral dynamics, and design options
based on combined steering and di?erential brake action are discussed.
Keywords: tracking control, articulated truck, truck platoon, loop shaping, di?erential
brake
1. INTRODUCTION
Introduction of new technologies in the automotive industry
has stimulated the emergence of Intelligent Vehicles(
IV) and vehicle platoons which are considered
as a prospective solution to improve tra?c capacity
without vast investments in new roadways.
In terms of reliance on the underlying information system,
applications fall into two categories: Autonomous
Intelligent Vehicles (AIVs) and Cooperative Intelligent
Vehicles (CIVs) (Bishop 2004). AIVs rely on
instrumentation and intelligence within the vehicles
or between vehicles in a platoon. CIVs need assistance
from the roadways. The common assumption of a
CIV system is a roadway with embedded magnetic
markers which give vehicles lateral reference signals or
coordinates. The majority of research on IV Systems
is on cooperative systems. California PATH program
has performed extensive studies for passenger car platoons,
truck and bus convoys. Both longitudinal and
lateral control algorithms have been studied and veri-
fied in field experiments. However, the vast investment
in renovating current highway systems constrains the
implementation in the near future.
Autonomous intelligent systems have the advantage of
no investment in the roadways. The benefits of such
an Intelligent Platoon of Heavy-duty Vehicles(IPHV)
to freight shipping companies are also obvious due to
the saving of driver expenses and fuel cost (Liang et al.
2003). The basic idea of IPHV is the tight following of
Articulated Vehicles, with a human driver in the lead
truck, and automatically controlled followers. Such
a truck platoon can be operated on both highways
and other truck routes. The Lead Vehicle is taken
as reference by the following vehicle. The necessary
infrastructures have been discussed in the literature
(Fritz 1999). Prominent is the European Chau?eur
program which has shown the technical possibility and
fuel consumption reduction of such proposals (Bonnet
and Fritz 2000). According to field experiment, saving
in fuel consumption of the Chau?eur platoon will be
around 20% on the follower. The potential drawback
of AIVs is the limit on the size of the platoon because
autonomous platoons pose stability problems. Thus
implementations at the present focus on autonomous
platoons consisting of 2 or 3 trucks which are likely
to be the most feasible AIV implementation in the
near feature. In this study, a platoon consisting of two
heavy vehicles is assumed, as shown in Fig. 1.
For the purpose of longitudinal distance and speed
regulation and lateral tracking in an autonomous platoon,
the relative longitudinal distance, relative speed
.....