ISO 9815:2010
(Main)Road vehicles — Passenger-car and trailer combinations — Lateral stability test
Road vehicles — Passenger-car and trailer combinations — Lateral stability test
ISO 9815:2010 specifies a lateral stability test for passenger-car and trailer combinations. It is applicable to passenger cars in accordance with ISO 3833, and also to light trucks, and their trailer combinations. The lateral stability test determines the damping characteristic of the yaw oscillation of such towing-vehicle–trailer combinations excited by a defined steering impulse. The combination is initially driven in a steady-state, straight-ahead driving condition. Oscillation of the vehicle is then initiated by the application of a single impulse of steering, followed by a period in which steering is held fixed and the oscillation of the combination is allowed to damp out. Testing is conducted at several constant speeds. Where non-periodic instability is of interest, a steady-state circular test is specified.
Véhicules routiers — Ensembles voiture particulière et remorque — Essai de stabilité latérale
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INTERNATIONAL ISO
STANDARD 9815
Third edition
2010-05-01
Road vehicles — Passenger-car and
trailer combinations — Lateral stability
test
Véhicules routiers — Ensembles voiture particulière et remorque —
Essai de stabilité latérale
Reference number
©
ISO 2010
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ii © ISO 2010 – All rights reserved
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms, definitions and symbols .1
4 Measurement variables.2
5 General conditions .2
5.1 Compliance .2
5.2 Measuring equipment .2
5.3 Test track.3
5.4 Wind velocity .3
5.5 Loading conditions .3
6 Test method .5
6.1 General .5
6.2 Test runs.5
7 Data analysis.7
7.1 General .7
7.2 Individual test runs.8
7.3 Zero-damping speed .10
7.4 Reference-damping speed.10
7.5 Reference-speed damping.11
8 Data presentation .11
8.1 General data.11
8.2 Test conditions .11
8.3 Results.11
Annex A (normative) Test report — General data (supplement to ISO 15037-1:2006, Annex A).12
Annex B (normative) Test results.15
Annex C (normative) Steady-state behaviour.16
Bibliography.17
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 9815 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 9, Vehicle
dynamics and road-holding ability.
This third edition cancels and replaces the second edition (ISO 9815:2003), which has been technically
revised.
iv © ISO 2010 – All rights reserved
Introduction
The main purpose of this International Standard is to provide repeatable and discriminatory test results.
The dynamic behaviour of a road vehicle is a very important aspect of active vehicle safety. Any given vehicle,
together with its driver and the prevailing environment, constitutes a closed-loop system that is unique. The
task of evaluating the dynamic behaviour is therefore very difficult since the significant interaction of these
driver-vehicle-environment elements are each complex in themselves. A complete and accurate description of
the behaviour of the road vehicle must necessarily involve information obtained from a number of different
tests.
Since this test method quantifies only one small part of the complete vehicle handling characteristics, the
results of these tests can only be considered significant for a correspondingly small part of the overall dynamic
behaviour.
Moreover, insufficient knowledge is available concerning the relationship between overall vehicle dynamic
properties and accident avoidance. A substantial amount of work is necessary to acquire sufficient and
reliable data on the correlation between accident avoidance and vehicle dynamic properties in general and the
results of these tests in particular. Consequently, any application of this test method for regulation purposes
requires proven correlation between test results and accident statistics.
INTERNATIONAL STANDARD ISO 9815:2010(E)
Road vehicles — Passenger-car and trailer combinations —
Lateral stability test
1 Scope
This International Standard specifies a lateral stability test for passenger-car and trailer combinations. It is
applicable to passenger cars in accordance with ISO 3833, and also to light trucks, and their trailer
combinations.
The lateral stability test determines the damping characteristic of the yaw oscillation of such towing-vehicle–
trailer combinations excited by a defined steering impulse. The combination is initially driven in a steady-state,
straight-ahead driving condition. Oscillation of the vehicle is then initiated by the application of a single
impulse of steering, followed by a period in which steering is held fixed and the oscillation of the combination
is allowed to damp out. Testing is conducted at several constant speeds. Where non-periodic instability is of
interest, a steady-state circular test is specified.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 1176, Road vehicles — Masses — Vocabulary and codes
ISO 2416, Passenger cars — Mass distribution
ISO 3833, Road vehicles — Types — Terms and definitions
ISO 4138:2004, Passenger cars — Steady-state circular driving behaviour — Open-loop test methods
ISO 8855, Road vehicles — Vehicle dynamics and road-holding ability — Vocabulary
ISO 15037-1:2006, Road vehicles — Vehicle dynamics test methods — Part 1: General conditions for
passenger cars
3 Terms, definitions and symbols
For the purposes of this document, the terms, definitions and symbols given in ISO 3833, ISO 8855 and the
following apply.
3.1
yaw articulation angle
∆ψ
angle of the X axis relative to the X axis, i.e. angle between the X axes of each of the two units, with the
C T
polarity determined by the rotation of the towing vehicle relative to the trailer
NOTE The letters “C” and “T” are used as subscripts to distinguish between variables associated with the towing
vehicle (car or light truck) and the trailer, respectively. For example, the longitudinal axis of the intermediate axis system of
the towing vehicle is designated as X , and the lateral acceleration of the trailer is designated as a .
C YT
3.2
mean gradient (of the test track)
G
change in elevation of the track surface between two points along the path of the vehicle divided by the
horizontal distance between those points, where the two points are those that define, as closely as is
practicable, that segment of the track travelled by the test vehicle between the times t and t , respectively
2 ∆ψn
For t and t , see 6.2.2 and 7.2.3, respectively.
2 ∆ψn
NOTE This gradient is dimensionless and is positive for a test vehicle travelling uphill and negative for a test vehicle
travelling downhill.
4 Measurement variables
When performing this test procedure, the following shall be measured:
⎯ steering-wheel angle, δ ,
H
⎯ longitudinal velocity of the towing vehicle, v ,
X
⎯ lateral acceleration of the trailer, a ,
XT
⎯ yaw articulation angle between towing vehicle and trailer, ∆ψ.
The following should be measured:
dψ
C
⎯ yaw velocity of the towing vehicle, ;
dt
dψ
T
⎯ yaw velocity of the trailer, .
dt
NOTE These variables are not intended to comprise a complete list.
5 General conditions
5.1 Compliance
The general conditions of the test shall be in accordance with ISO 15037-1, with the additions and exceptions
given in this clause.
5.2 Measuring equipment
The measurement variables given in Clause 4 shall be monitored using appropriate transducers. The
requirements of ISO 15037-1 regarding measurement and recording equipment shall be applied to both
towing vehicle and trailer. Typical operating ranges and recommended maximum errors for variables not
considered by ISO 15037-1 are given in Table 1.
A steering-wheel stop or marking may be used. The use of a steering machine is optional.
Table 1 — Variables, operating ranges and recommended maximum errors —
Addendum to ISO 15037-1:2006, Table 1
Recommended maximum error
Variable Typical operating range
(of combined transducer/recorder system)
Articulation angle ± 20° ± 0,2°
2 © ISO 2010 – All rights reserved
5.3 Test track
In addition to the test track requirements of ISO 15037-1, the mean gradient of the test track along the path of
the vehicle, G , shall be within the range ± 0,01. G shall be recorded for each test run. See 6.2.1 and 7.2.1 for
related requirements. In addition, the test surface shall be maintained over a track with a minimum width of
8 m. An increased run-off area should be provided in addition to the specified test surface.
Inasmuch as yaw damping of articulated vehicles is known to be sensitive to the longitudinal slope of the test
track, the test should be conducted in both directions whenever G approaches the allowed maximum.
5.4 Wind velocity
Wind velocity
...
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