ISO 19364:2016

Passenger cars — Vehicle dynamic simulation and validation — Steady-state circular driving behaviour

ISO 19364:2016 specifies a method for comparing computer simulation results from a vehicle mathematical model to measured test data for an existing vehicle according to steady-state circular driving tests as specified in ISO 4138 or the Slowly Increasing Steer Test that is an alternative to ISO 4138. The comparison is made for the purpose of validating the simulation tool for this type of test when applied to variants of the tested vehicle. It is applicable to passenger cars as defined in ISO 3833. NOTE The Slowly Increasing Steer method is described in regulations such as USA FMVSS 126 "Federal Register Vol 72, No. 66, April 6, 2007" and UN/ECE Regulation No. 13-H, "Uniform provisions concerning the approval of passenger cars with regard to braking".

Voitures particulières — Simulation et validation dynamique des véhicules — Tenue de route en régime permanent sur trajectoire circulaire

General Information

• Status: Published
• Publication Date: 04-Oct-2016
• ICS: 43.100 - Passenger cars. Caravans and light trailers
• Technical Committee: ISO/TC 22/SC 33 - Vehicle dynamics and chassis components
• Drafting Committee: ISO/TC 22/SC 33/WG 11 - Simulation
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 16-Aug-2023

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19364
First edition
2016-10-01
Passenger cars — Vehicle dynamic
simulation and validation — Steady-
state circular driving behaviour
Voitures particulières — Simulation et validation dynamique des
véhicules — Tenue de route en régime permanent sur trajectoire
circulaire
Reference number
ISO 19364:2016(E)
©
ISO 2016

---------------------- Page: 1 ----------------------
ISO 19364:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2016 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 19364:2016(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Variables . 2
6 Simulation tool requirements . 2
6.1 General . 2
6.2 Mass and inertia . 3
6.3 Tires . 3
6.4 Suspensions . 3
6.5 Steering system . 3
6.6 Aerodynamics . 4
6.7 Brake system . 4
6.8 Powertrain . 4
6.9 Active controllers . 4
6.10 Data acquisition . 4
6.11 Driver controls . 4
7 Physical testing. 4
7.1 General . 4
7.2 Test methods . 5
7.2.1 Constant-radius . 5
7.2.2 Constant speed . 5
7.3 Documentation of limit condition . 5
7.4 Low-pass filtering of measured data . 5
8 Simulation . 6
8.1 General . 6
8.2 Simulation procedure . . 6
8.2.1 Direction of steer . 6
8.2.2 Tests with steady-state conditions . 6
8.2.3 Tests with slowly changing conditions . 6
8.3 Data recording . 6
8.3.1 General. 6
8.3.2 Tests with steady-state conditions . 6
8.3.3 Tests with slowly changing conditions . 7
9 Comparison between simulation and physical test results . 7
9.1 General . 7
9.2 Calculation of boundary points. 7
9.3 Tolerances for cross-plot boundary points. 9
9.4 Comparison of simulation cross plots with measured test data . 9
10 Documentation . 9
Annex A (informative) Combined tolerance for normalized geometric profile .11
Bibliography .13
© ISO 2016 – All rights reserved iii

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ISO 19364:2016(E)

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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 22, Road vehicles, Subcommittee SC 33, Vehicle
dynamics and chassis components.
iv © ISO 2016 – All rights reserved

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ISO 19364:2016(E)

Introduction
The main purpose of this document is to provide a repeatable and discriminatory method for comparing
simulation results to measured test data from a physical vehicle for a specific type of test.
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
interactions of these driver–vehicle–environment elements are each complex in themselves. A complete
and accurate description of the behaviour of the road vehicle should include information obtained from
a number of different tests.
Since this test method quantifies only one small part of the complete vehicle handling characteristics,
the validation method associated with this test can only be considered significant for a correspondingly
small part of the overall dynamic behaviour.
© ISO 2016 – All rights reserved v

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INTERNATIONAL STANDARD ISO 19364:2016(E)
Passenger cars — Vehicle dynamic simulation and
validation — Steady-state circular driving behaviour
1 Scope
This document specifies a method for comparing computer simulation results from a vehicle
mathematical model to measured test data for an existing vehicle according to steady-state circular
driving tests as specified in ISO 4138 or the Slowly Increasing Steer Test that is an alternative to
ISO 4138. The comparison is made for the purpose of validating the simulation tool for this type of test
when applied to variants of the tested vehicle.
It is applicable to passenger cars as defined in ISO 3833.
NOTE The Slowly Increasing Steer method is described in regulations such as USA FMVSS 126 “Federal
Register Vol 72, No. 66, April 6, 2007” and UN/ECE Regulation No. 13-H, “Uniform provisions concerning the
approval of passenger cars with regard to braking”.
2 Normative references
The following documents are referred to in text in such a way that some or all of their content
constitutes requirements 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 4138, Passenger cars — Steady-state circular driving behaviour — Open-loop test methods
ISO 15037-1, Road vehicles — Vehicle dynamics test methods — Part 1: General conditions for passenger cars
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1176, ISO 2416, ISO 3833,
ISO 8855 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
simulation
calculation of motion variables of a vehicle from equations in a mathematical model of the vehicle system
3.2
simulation tool
simulation environment including software, models, input data, and hardware case of hardware-in-the-
loop simulation
3.3
cross plot
plot where the horizontal axis shows values for a variable other than time (e.g. lateral acceleration)
© ISO 2016 – All rights reserved 1

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ISO 19364:2016(E)

4 Principle
Open-loop test methods defined in ISO 4138 are used to determine the steady-state circular driving
behaviour of passenger cars as defined in ISO 3833.
The test characterizes vehicle-handling behaviour in steady-state conditions covering a range of
cornering conditions from straight-line up to limit conditions for steering control. Results are typically
reported by cross plotting steady-state measures of variables of interest against steady-state levels of
lateral acceleration, and possibly calculating characteristic values based on gradients of the plotted data.
Within this document, the purpose of the test is to demonstrate that a vehicle simulation tool can
predict the vehicle behaviour within specified tolerances. The vehicle simulation tool is used to simulate
a specific existing vehicle running through a steady-state test as specified in ISO 4138, or, alternatively,
a Slowly Increasing Steer Test used in stability control evaluation. Simulation results are used to define
graphical boundaries for overlaid cross-plots, and the data from physical testing are overlaid to see if
the measurements fall within the acceptable ranges.
NOTE This document may be used for several purposes. Depending on the purpose of the validation, only
parts of the validation requirements may be met.
The existing vehicle is physically tested at least three times to allow the test data to be compared with
the simulation results.
5 Variables
The following variables shall be compared:
— lateral acceleration;
— steering-wheel angle;
— sideslip angle;
— roll angle.
The steering-wheel torque shall also be compared if this document is used to validate a simulation
tool for the purpose of predicting steering torque during steady-state circular driving as defined in
ISO 4138.
Measurement requirements shall be taken from ISO 4138 and ISO 15037-1, unless noted otherwise.
For the purpose of this document, lateral acceleration should be measured directly by an inertial
measurement unit, rather than using the alternative calculation methods provided in ISO 4138.
6 Simulation tool requirements
6.1 General
The simulation tool used to predict behaviour of a vehicle of interest shall include a mathematical model
capable of calculating variables of interest for the test procedures being simulated. In this document,
the mathematical model is used to simulate a steady-state cornering manoeuvres (see 7.2) and provide
calculated values of the variables of interest from Clause 5.
The procedure for obtaining input data from experiments may differ for simulation tools, however, the
input data shall not be manipulated for better correlation. However, adaptation of input data to actual
testing conditions such as road friction should be allowed.
NOTE Active controllers and active intervention systems that prevent a steady-state condition from being
established are not relevant for the tests covered in this document.
2 © ISO 2016 – All rights reserved

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ISO 19364:2016(E)

6.2 Mass and inertia
The mathematical model should include all masses, such as the chassis, engine, payloads, unsprung
masses, etc. The value of the mass and the location of the centre of mass are essential properties of the
vehicle for the tests covered in this document. On the other hand, moments and products of inertia have
no effect under steady-state conditions, when angular accelerations are negligible.
Vehicles with significant torsional frame compliance require a more detailed representation that
includes frame-twist effects that occur in extreme manoeuvres.
6.3 Tires
The vertical, lateral, and longitudinal forces and moments where each tire contacts the ground
provide the main actions on the vehicle. The fidelity of the prediction of vehicle movement depends
on the fidelity of the calculated tire forces and moments. Differences between the tire force and
moment measurements used for the model and those of used in vehicle testing can be expected due to
different wear and aging histories. Although difficult to account for these differences, it is important to
acknowledge and understand them.
Large lateral slip angles and inclination can occur under the conditions covered in this document.
Longitudinal slip ratios are usually limited to the amounts needed to generate longitudinal forces to
maintain a target speed in the test. The tire model shall cover the entire ranges of slip (lateral and
longitudinal), inclination angle relative to the ground, and load that occur in the tests being simulated.
The surface friction coefficient between the tire and ground is an important property for the limit
friction conditions that can be encountered in steady-state circular driving tests.
The simulated tests take place on a flat homogenous surface; detailed tire models that handle uneven
surfaces are not needed. If the test surface has inclination for water drainage, this should be included in
the simulation.
The simulated tests involve conditions that are intended to be steady-state; therefore, transient effects
in tire response (e.g. relaxation length) are not needed.
6.4 Suspensions
The properties of the suspensions that determine how the tire is geometrically located, oriented, and
loaded against the ground shall be represent
...

DRAFT INTERNATIONAL STANDARD
ISO/DIS 19364
ISO/TC 22/SC 33 Secretariat: DIN
Voting begins on: Voting terminates on:
2015-02-19 2015-05-19
Passenger cars — Vehicle dynamic simulation and
validation — Steady-state circular driving behaviour
Voitures particulières — Simulation et validation dynamique des véhicules — Tenue de route en régime
permanent sur trajectoire circulaire
ICS: 43.100
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 19364:2014(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2014

---------------------- Page: 1 ----------------------
ISO/DIS 19364:2014(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 19364:2015(E)
© ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or
utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or
posting on the internet or an intranet, without prior written permission. Permission can be requested
from either ISO at the address below or ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland.
Contents
This template allows you to work with default MS Word functions and styles. You can use these if you
want to maintain the Table Of Contents automatically and apply auto-numbering if this is your
preference. Delete this Table of Contents if not required.
Foreword . 5
Introduction. 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Principle . 8
5 Variables. 8
6 Simulation Tool Requirements . 8
6.1 General . 8
6.2 Mass and inertia . 9
6.3 Tires . 9
6.4 Suspensions . 9
6.5 Steering system . 10
6.6 Aerodynamics . 10
6.7 Brake system . 10
6.8 Powertrain . 10
2 © ISO 19364 – All rights reserved

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ISO 19364:2015 (E)
6.9 Active controllers . 10
6.10 Data Acquisition . 11
6.11 Driver controls . 11
7 Physical Testing . 11
7.1 General . 11
7.2 Test Methods . 11
7.2.1 Constant-radius . 11
7.2.2 Constant speed . 11
7.3 Documentation of limit condition . 12
7.4 Low-pass filtering of measured data . 12
8 Simulation . 12
8.1 General . 12
8.2 Simulation Procedure . 12
8.2.1 Direction of steer . 12
8.2.2 Tests with steady state conditions . 12
8.2.3 Tests with slowly changing conditions . 13
8.3 Data recording . 13
8.3.1 General . 13
8.3.2 Tests with steady state conditions . 13
8.3.3 Tests with slowly changing conditions . 13
9 Comparison between simulation and physical test results . 13
9.1 General . 13
9.2 Calculation of boundary points . 14
9.3 Tolerances for cross-plot boundary points . 16
9.4 Comparison of simulation cross plots with measured test data . 16
10 Documentation . 16
Annex A (informative) Combined Tolerance for Normalized Geometric Profile . 18

© ISO 19364 – All rights reserved 3

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ISO 19364:2015 (E)
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO's adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC22/SC9 which will be in 2015 TC22/SC33.

© ISO 19364 – All rights reserved 5

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ISO 19364:2015(E)
Introduction
The main purpose of this 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 will require proven correlation between test results and accident
statistics.

6 © ISO 19364 – All rights reserved

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ISO 19364:2015 (E)
Passenger cars — Vehicle dynamic simulation and validation —
Steady-state circular driving behaviour
1 Scope
This International Standard specifies a method for comparing computer simulation results from a
vehicle mathematical model to measured test data for an existing vehicle according to steady-state
circular driving tests as specified in ISO 4138 or the Slowly Iincreasing Steer test that is an alternative
to ISO 4138. The comparison is made for the purpose of validating the simulation tool for this type of
test when applied to variants of the tested vehicle.
It is applicable to passenger cars as defined in ISO 3833.
NOTE The Slowly Increasing Steer method is described in regulations such as USA FMVSS 126 “Federal
Register Vol 72, No. 66, April 6, 2007” and UN/ECE Regulation No. 13-H, “Uniform provisions
concerning the approval of passenger cars with regard to braking.”
2 Normative references
The following referenced documents are indispensable for the application of this document. For these
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, 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, Road vehicles — Vehicle dynamics test methods — Part 1: General conditions for passenger
cars
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1176, ISO 2416, ISO 3833,
ISO 8855 and the following apply.
3.1
simulation
calculation of motion variables of a vehicle from equations in a mathematical model of the vehicle
system
3.2
simulation tool
simulation environment including software, models, input data, and hardware in case of hardware in
the loop simulation
3.3
cross plot
plot where the horizontal axis shows values for a variable other than time (e.g., lateral acceleration)
© ISO 19364 – All rights reserved 7

---------------------- Page: 7 ----------------------
ISO 19364:2015(E)
4 Principle
Open-loop test methods defined in ISO 4138 are used to determine the steady-state circular driving
behaviour of passenger cars as defined in ISO 3833.
The test characterizes vehicle-handling behaviour in steady-state conditions covering a range of
cornering conditions from straight-line up to limit conditions for steering control. Results are typically
reported by cross plotting steady-state measures of variables of interest against steady-state levels of
lateral acceleration, and possibly calculating characteristic values based on gradients of the plotted
data.
Within this International Standard, the purpose of the test is to demonstrate that a vehicle simulation
tool can predict the vehicle behaviour within specified tolerances. The vehicle simulation tool is used to
simulate a specific existing vehicle running through a steady-state test as specified in ISO 4138, or,
alternatively, a Slowly Increasing Steer test used in stability control evaluation. Simulation results are
used to define graphical boundaries for overlaid cross-plots, and the data from physical testing are
overlaid to see if the measurements fall within the acceptable ranges.
NOTE This International Standard may be used for several purposes. Depending on the purpose of the
validation, only parts of the validation requirements may be met.
The existing vehicle is physically tested at least three times to allow the test data to be compared with
the simulation results.
5 Variables
The following variables shall be compared:
 Lateral acceleration
 Steering wheel angle
 Side slip angle
 Roll angle
The steering wheel torque shall also be compared if this International Standard is used to validate a
simulation tool for the purpose of predicting steering torque during steady-state circular driving as
defined in ISO 4138.
Measurement requirements shall be taken from ISO 4138 and ISO 15037-1 unless noted otherwise.
NOTE For the purpose of this International Standard, lateral acceleration should be measured directly
by an inertial measurement unit, rather than using the alternative calculation methods provided in ISO
4138.
6 Simulation Tool Requirements
6.1 General
The simulation tool used to predict behaviour of a vehicle of interest shall include a mathematical
model capable of calculating variables of interest for the test procedures being simulated. In this
8 © ISO 19364 – All rights reserved

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ISO 19364:2015 (E)
International Standard, the mathematical model is used to simulate a steady-state cornering manoeuvre
(see 7.2) and provide calculated values of the variables of interest from Clause 5.
NOTE 1 Procedure for obtaining input data from experiments may differ for simulation tools, however,
the input data should not be manipulated for better correlation.
NOTE 2 Active controllers and active intervention systems that prevent a steady state condition
from being established are not relevant for the tests covered in this International Standard.
6.2 Mass and inertia
The mathematical model should include all masses, such as the chassis, engine, payloads, unsprung
masses, etc. The value of the mass and the location of the centre of mass are essential properties of the
vehicle for the tests covered in this International Standard. On the other hand, moments and products of
inertia have no effect under steady-state conditions, when angular accelerations are negligible.
Vehicles with significant torsional frame compliance require a more detailed representation that
includes frame-twist effects that occur in extreme manoeuvres.
6.3 Tires
The vertical, lateral, and longitudinal forces and moments where each tire contacts the ground provide
the main actions on the vehicle. The fidelity of the prediction of vehicle movement depends on the
fidelity of the calculated tire forces and moments.
Large lateral slip angles can occur under the conditions covered in this International Standard.
Longitudinal slip ratios are usually limited to the amounts needed to generate longitudinal forces to
maintain a target speed in the test. The tire model should cover the entire ranges of slip (lateral and
longitudinal), inclination angle relative to the ground, and load that occur in the tests being simulated.
The surface friction coefficient between the tire and ground is an important property for the limit
friction conditions that can be encountered in steady-state circular driving tests.
The simulated tests take place on a flat homogenous surface; detailed tire models that handle uneven
surfaces are not needed.
The simulated tests involve conditions that are intended to be steady state; therefore, transient effects
in tire response (e.g.,
...