1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 4138:2012Passenger cars Steady-statecircular driving behaviour Open-loop test methodsBS ISO 4138:2012 BRITISH STANDARDNational forewordThis British Standard is the UK impl
2、ementation of ISO 4138:2012. Itsupersedes BS ISO 4138:2004 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee AUE/15, Safety related to vehicles.A list of organizations represented on this committee can beobtained on request to its secretary.This publicati
3、on does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 67590 4ICS 43.100Compliance with a British Standard cannot confer immunity fromlega
4、l obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 August 2012.Amendments issued since publicationDate Text affectedBS ISO 4138:2012 ISO 2012Passenger cars Steady-state circular driving behaviour Open-loop test methodsVoitures pa
5、rticulires Tenue de route en rgime permanent sur trajectoire circulaire Mthodes dessai en boucle ouverteINTERNATIONAL STANDARDISO4138Fourth edition2012-06-01Reference numberISO 4138:2012(E)BS ISO 4138:2012ISO 4138:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights
6、reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the re
7、quester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 4138:2012ISO 4138:2012(E) ISO 2012 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope 12 Normative references
8、 . 13 Terms and definitions . 14 Principle . 14.1 Test methods 14.2 Equivalence of test methods 25 Variables 25.1 Reference system 25.2 Measurement 26 Measuring equipment . 36.1 Description 36.2 Transducer installation 36.3 Data processing . 37 Test conditions . 38 Test procedure . 38.1 Warm-up . 38
9、.2 Initial driving condition 38.3 General test description 48.4 Method 1 Constant radius 48.5 Method 2 Constant steering-wheel angle 58.6 Method 3 Constant speed 59 Data analysis 69.1 General . 69.2 Lateral acceleration 69.3 Path radius 710 Data evaluation and presentation of results 710.1 General .
10、 710.2 Plotted results (see also Annex A) 710.3 Evaluation of characteristic values 8Annex A (normative) Presentation of results 12Annex B (normative) Determination of overall (static) steering ratio 17Annex C (informative) General information Theoretical basis for the test methods 18Bibliography .1
11、9BS ISO 4138:2012ISO 4138:2012(E)ForewordISO (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 inter
12、ested 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
13、 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 tech
14、nical 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 s
15、hall not be held responsible for identifying any or all such patent rights.ISO 4138 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 9, Vehicle dynamics and road-holding ability.This fourth edition cancels and replaces the third edition (ISO 4138:2004), which has been te
16、chnically revised.iv ISO 2012 All rights reservedBS ISO 4138:2012ISO 4138:2012(E)IntroductionThe 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
17、 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 drivervehicleenvironment elements are each complex in themselves. A
18、 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 consid
19、ered 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
20、 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. ISO 2012
21、 All rights reserved vBS ISO 4138:2012BS ISO 4138:2012Passenger cars Steady-state circular driving behaviour Open-loop test methods1 ScopeThis International Standard specifies open-loop test methods for determining the steady-state circular driving behaviour of passenger cars as defined in ISO 3833
22、and of light trucks, such behaviour being one of the factors comprising vehicle dynamics and road-holding properties. The open-loop manoeuvres included in these methods are not representative of real driving conditions, but are nevertheless useful for obtaining measures of vehicle steady-state behav
23、iour resulting from several specific types of control inputs under closely controlled test conditions.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the lat
24、est edition of the referenced document (including any amendments) applies.ISO 3833:1977, Road vehicles Types Terms and definitionsISO 8855:2011, Road vehicles Vehicle dynamics and road-holding ability VocabularyISO 15037-1:2006, Road vehicles Vehicle dynamics test methods Part 1: General conditions
25、for passenger cars3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 8855 and the following apply.3.1low-speed path radiusradius of the circular path transcribed by the origin of the vehicle axis system when the vehicle is operated at constant speed with
26、 a given fixed steering-wheel angle and with approximately zero lateral acceleration4 Principle4.1 Test methodsThree test methods are specified: Method 1, the constant-radius test method; Method 2, the constant steering-wheel angle test method; Method 3, the constant-speed test method.Each method is
27、 presented with two variations and differs in requirements for testing space, driver skill and instrumentation. Methods 1 and 3 depend upon the path-keeping ability of the driver to minimize instrumentation requirements. Method 2 uses fixed steering-wheel angle and calculates path radius from measur
28、es of inertial instruments.INTERNATIONAL STANDARD ISO 4138:2012(E) ISO 2012 All rights reserved 1BS ISO 4138:2012ISO 4138:2012(E)4.2 Equivalence of test methodsThe nature of any stable steady-state is independent of the method by which it is achieved. Therefore, to obtain a desired set of steady-sta
29、te equilibrium conditions of speed, steering-wheel angle and turning radius, it is possible to hold any one of them constant, vary the second and measure the third. Thus, either a constant-radius test method (in which speed is varied and steering-wheel angle is measured), a constant steering-wheel a
30、ngle test method (in which speed is varied and radius is calculated from variables of vehicle motion) or a constant-speed test method (in which radius is varied and steering-wheel angle is either measured or varied and the radius calculated from variables of vehicle motion) may be used. The conditio
31、ns that are to be held constant, varied and measured or calculated are summarized in Table 1.Table 1 Test conditionsTest method Constant VariedMeasured or calculatedConstant radius Radius Speed Steering-wheel angleConstant steering-wheel angle Steering-wheel angle Speed RadiusConstant speed with dis
32、crete turn radii Speed Radius Steering-wheel angleConstant speed with discrete steering-wheel anglesSpeed Steering-wheel angle RadiusAll three test methods will produce equivalent steady-state results, provided they span the same combination of speedsteerradius steady-state conditions. Moreover, in
33、principle, an equivalent to any of the methods can be obtained by cross plotting a series of results from one to produce the results from another.EXAMPLE Taking points at constant speed from a series of constant-radius tests run on different turn radii.In practice, however, results obtained from tes
34、ts conducted with different combinations of speed, steer and radius may differ due to differences in road-load throttle, aerodynamics, tyre slip and inclination angles at different steering angles, etc. Also, the steering system is nonlinear in many vehicles and does not have a fixed overall steerin
35、g ratio. Gradients obtained using one method at a given steady-state equilibrium condition can differ from those obtained using another and, whereas in one method lateral acceleration is controlled by changing speed, in another it is controlled by changing the steering-wheel angle. Practical conside
36、rations such as tyre heating during long test runs and failure to maintain true steady-state also tend to affect test results.5 Variables5.1 Reference systemThe provisions given in ISO 15037-1 apply.5.2 MeasurementMeasure the following variables:a) longitudinal velocity, vX.b) lateral acceleration,
37、aY;c) steering-wheel angle, H.Alternatively, lateral acceleration may be determined from other motion variables (see 9.2).NOTE The method chosen to determine lateral acceleration could require the measurement of additional variables (yaw velocity, vehicle roll angle or sideslip angle) for use in the
38、 computation.2 ISO 2012 All rights reservedBS ISO 4138:2012ISO 4138:2012(E)The following variables should also be measured: yaw velocity, dd t ; sideslip angle, , and/or lateral velocity, vY; longitudinal acceleration, aX; vehicle roll angle, V; steering-wheel torque, MH.The front steer angle, F, an
39、d rear steer angle, R, may also be measured.6 Measuring equipment6.1 DescriptionThe variables selected for test purposes shall be measured using appropriate transducers and the data recorded on a multi-channel recording system having a time base. Typical operating ranges and recommended maximum erro
40、rs of the transducer and recording system are given in ISO 15037-1 and Table 2.6.2 Transducer installationThe transducer installation shall be in accordance with ISO 15037-1:2006, 4.2.6.3 Data processingThe provisions given in ISO 15037-1:2006, 4.3, apply.Table 2 Variables, their typical operating r
41、anges and recommended maximum errorsVariable Typical operating rangeRecommended maximum error of the combined transducer/recorder systemFront-steer angle 20 0,2Rear-steer angle 10 0,1NOTE Increased measurement accuracy could be desirable for computation of some of the characteristic values given in
42、10.3.7 Test conditionsTest conditions shall be in accordance with ISO 15037-1:2006, Clause 5. General data on the test vehicle shall be recorded as specified in ISO 15037-1:2006, 5.4.1. In addition, the tyre type, tyre brand, any special equipment on the test vehicle, any deviation in type or operat
43、ing condition of components from the manufacturers specification, the odometer reading at the beginning and end of the test, and any other condition that could affect test results shall be recorded on the test report for general data (see ISO 15037-1:2006, Annex A).8 Test procedure8.1 Warm-upThe war
44、m-up shall be carried out in accordance with ISO 15037-1:2006, 6.1.8.2 Initial driving conditionThe conditions shall be in accordance with 15037-1:2006, 6.2.1 and 6.2.3, and with 8.3 to 8.6 as follows, according to which method and variation is used. ISO 2012 All rights reserved 3BS ISO 4138:2012ISO
45、 4138:2012(E)8.3 General test descriptionAll necessary variables shall be recorded throughout the manoeuvre. Data shall be taken for both left and right turns.For tests utilizing discrete increments of speed, radius or steering-wheel angle, all of the test data may be taken in one turning direction
46、followed by all the data in the other turning direction, as experience has shown that this minimizes data scatter. However, to obtain more even tyre wear and reduced tyre heating, data may be taken in alternating turning directions at each test speed/radius/steering-wheel angle.The method chosen sha
47、ll be noted on the test report, in the section on test-method-specific data for test conditions (see ISO 15037-1:2006, Annex B). At a minimum, data shall be taken at increments of lateral acceleration no larger than 0,5 m/s2.NOTE Where data vary rapidly with changes in lateral acceleration, it can b
48、e useful to decrease the speed/radius/steering-wheel angle increments.The test should be repeated several times so that the results can be examined for repeatability and averaged.Caution should be exercised during testing so that tyre heating is minimized as much as possible. Tyre heating is a parti
49、cular concern for test methods using continuous speed increase, with attendant long periods of data acquisition, and for all test methods at high levels of lateral acceleration. The tyres should be cooled to normal operating temperatures between test runs.8.4 Method 1 Constant radius8.4.1 DescriptionThis test method requires driving the test vehicle at several speeds over a circular path of known radius. The standard radius of the path shall be 100 m, but larger and smaller radii may be us
