1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 7401:2011Road vehicles Lateraltransient response testmethods Open-loop testmethodsBS ISO 7401:2011 BRITISH STANDARDNational forewordThis British Standard is the UK impleme
2、ntation of ISO 7401:2011. Itsupersedes BS ISO 7401:2003 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee AUE/15, Safety related to vehicles.A list of organizations represented on this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 publication
3、does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 67591 1ICS 43.020; 43.100Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the autho
4、rity of theStandards Policy and Strategy Committee on 30 June 2011.Amendments issued since publicationDate Text affectedBS ISO 7401:2011Reference numberISO 7401:2011(E)ISO 2011INTERNATIONAL STANDARD ISO7401Third edition2011-04-15Road vehicles Lateral transient response test methods Open-loop test me
5、thods Vhicules routiers Mthodes dessai de rponse transitoire latrale Mthodes dessai en boucle ouverte BS ISO 7401:2011ISO 7401:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by an
6、y 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 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
7、copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedBS ISO 7401:2011ISO 7401:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv Introduction.v 1 Scope1 2 Normative references1 3 Terms and definitions .1 4 General conditions1 5 Principle .2 6 Refere
8、nce system3 7 Variables.3 8 Measuring equipment .4 9 Test conditions4 10 Step input .5 11 Sinusoidal input one period (see ISO/TR 8725) .7 12 Random input (see ISO/TR 8726) .9 13 Pulse input .11 14 Continuous sinusoidal input12 Annex A (normative) Test report General data .14 Annex B (normative) Tes
9、t report Presentation of results 16 Bibliography22 BS ISO 7401:2011ISO 7401:2011(E) iv ISO 2011 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standar
10、ds 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
11、 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
12、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
13、 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 7401 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 9, Vehicle dynamics and road-holding ability. This
14、third edition cancels and replaces the second edition (ISO 7401:2003), which has been technically revised. BS ISO 7401:2011ISO 7401:2011(E) ISO 2011 All rights reserved vIntroduction The main purpose of this International Standard is to provide repeatable and discriminatory test results. The dynamic
15、 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 significan
16、t interaction of these driver-vehicle-environment elements is each complex in itself. 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
17、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 acciden
18、t 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 purpos
19、es will require proven correlation between test results and accident statistics. BS ISO 7401:2011BS ISO 7401:2011INTERNATIONAL STANDARD ISO 7401:2011(E) ISO 2011 All rights reserved 1Road vehicles Lateral transient response test methods Open-loop test methods 1 Scope This International Standard spec
20、ifies open-loop test methods for determining the transient response behaviour of road vehicles. It is applicable to passenger cars, as defined in ISO 3833, and to light trucks. NOTE The open-loop manoeuvres specified in this International Standard are not representative of normal driving conditions,
21、 but are nevertheless useful for obtaining measures of vehicle transient behaviour in response to several specific types of steering input under closely controlled test conditions. For measurements of steady-state properties, see ISO 4138. 2 Normative references The following referenced documents ar
22、e 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 1176:1990, Road vehicles Masses Vocabulary and codes ISO 2416:1992, Passenger cars
23、 Mass distribution ISO/TR 8725:1988, Road vehicles Transient open-loop response test method with one period of sinusoidal input ISO/TR 8726:1988, Road vehicles Transient open-loop response test method with pseudo-random steering input ISO 88551), Road vehicles Vehicle dynamics and road-holding abili
24、ty Vocabulary ISO 15037-1:2006, 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 8855 apply. 4 General conditions The general conditions specified in ISO 15037-1
25、 shall apply. 1) To be published. BS ISO 7401:2011ISO 7401:2011(E) 2 ISO 2011 All rights reserved5 Principle 5.1 General IMPORTANT The method of data analysis in the frequency domain assumes that the vehicle has a linear response; this is unlikely to be the case over the whole range of lateral accel
26、erations of interest. The standard method of dealing with such a situation is to restrict the input to a sufficiently small range such that linear behaviour can be assumed. If necessary, testing can be performed with several ranges of inputs that, together, cover the entire range of interest. The pr
27、imary object of these tests is to determine the transient response behaviour of a vehicle. Characteristic values and functions in the time and frequency domains are considered necessary for characterizing vehicle transient response. Important characteristics in the time domain are: a) time lags betw
28、een steering-wheel angle, lateral acceleration and yaw velocity; b) response times of lateral acceleration and yaw velocity (see 10.2.1 and 10.2.2); c) lateral acceleration gain (lateral acceleration divided by steering-wheel angle); d) yaw velocity gain (yaw velocity divided by steering-wheel angle
29、); and e) overshoot values (see 10.2.3). These characteristics show correlation with subjective evaluation during road driving. Important characteristics in the frequency domain are the frequency responses, i.e. amplitudes and phases of: lateral acceleration related to steering-wheel angle; and yaw
30、velocity related to steering-wheel angle. 5.2 Test methods There are several test methods for obtaining these characteristics in the domains of time and frequency, the applicability of which depends in part on the size of the test track available. a) Time domain: 1) step input; and 2) sinusoidal inp
31、ut (one period). b) Frequency domain: 1) random input; 2) pulse input; and 3) continuous sinusoidal input. These test methods are optional, but at least one of each domain type should be performed. The methods chosen shall be indicated in the general data specified in Annex A and in the presentation
32、 of test results specified in Annex B. BS ISO 7401:2011ISO 7401:2011(E) ISO 2011 All rights reserved 3It is possible that the characteristic values of lateral acceleration gain and yaw velocity gain, obtained by the different test methods, may not be comparable, owing to one or more of the following
33、 circumstances: linear versus non-linear vehicle behaviour; periodic versus non-periodic steady-state condition; steady state versus dynamic vehicle behaviour. 6 Reference system The reference system specified in ISO 15037-1 shall apply. The location of the origin of the vehicle axis system (XV, YV,
34、 ZV) is the reference point and therefore should be independent of the loading condition. It is fixed in the longitudinal plane of symmetry at half-wheelbase and at the same height above the ground as the centre of gravity of the vehicle at complete vehicle kerb mass (see ISO 1176). 7 Variables The
35、following variables shall be determined: a) steering-wheel angle, H; b) lateral acceleration, aY; c) yaw velocity, ; d) longitudinal velocity, vX. The following variables may be determined: roll angle, ; sideslip angle, ; lateral velocity, vY; steering-wheel torque, MH. These variables, defined in I
36、SO 8855, are not intended to comprise a complete list. BS ISO 7401:2011ISO 7401:2011(E) 4 ISO 2011 All rights reserved8 Measuring equipment 8.1 Description Subclause 4.1 of ISO 15037-1:2006 shall apply as well as the following additions shown in Table 1. Table 1 Variables, typical operating ranges a
37、nd recommended maximum errors Variable Range Recommended maximum error of the combined transducer/ recorder system Steering-wheel angle 180 to +180a1 Yaw velocity 50 /s to +50 /s 0,5 /s Lateral velocity 10 m/s to +10 m/s 0,1 m/s Sideslip angle 15 to +15 0,3 aAssuming a conventional steering system.
38、The use of a programmable steer robot may help to increase the accuracy and repeatability of steer inputs for the described transient response manoeuvres. 8.2 Transducer installation Subclause 4.2 of ISO 15037-1:2006 shall apply. 8.3 Data processing The recording system and data processing requireme
39、nts contained in 4.3 of ISO 15037-1:2006 shall apply. 9 Test conditions 9.1 General The test conditions specified in Clause 5 of ISO 15037-1:2006 shall apply. 9.2 Vehicle loading conditions 9.2.1 General Tests shall be carried out at the minimum loading condition and at the maximum loading condition
40、 defined below, and at other loading conditions of interest. In accordance with ISO 1176:1990, 4.8 and 4.13, the maximum authorized total mass (Code: ISO-M08) and the maximum authorized axle load (Code: ISO-M13) shall not be exceeded. Care shall be taken to minimize the difference of both the locati
41、on of the centre of gravity and the moments of inertia as compared to the loading conditions of the vehicle in normal use (see ISO 2416:1992, Clause 4). The resulting static wheel loads shall be determined and recorded in the test report (see Annex A). BS ISO 7401:2011ISO 7401:2011(E) ISO 2011 All r
42、ights reserved 59.2.2 Minimum loading condition For the minimum loading condition, the total vehicle mass shall consist of the complete vehicle kerb mass (Code: ISO-M06) in accordance with ISO 1176:1990, 4.6, plus the masses of the driver and the instrumentation. The mass of the driver and the instr
43、umentation should not exceed 150 kg. The load distribution shall be equivalent to that of two occupants in the front seats, in accordance with ISO 2416. 9.2.3 Maximum loading condition For the maximum loading condition, the total mass shall be equal to the maximum authorized total mass. For the maxi
44、mum loading condition, the total mass shall be equivalent to the complete vehicle kerb mass, plus 68 kg for each seat in the passenger compartment and with the remaining maximum mass of transportable goods equally distributed over the luggage compartment in accordance with ISO 2416. Loading of the p
45、assenger compartment shall be such that the actual wheel loads are equal to those obtained by loading each seat with 68 kg according to ISO 2416. The transient lateral response is strongly influenced by the moments of inertia and by the height of the centre of gravity. Wheel loads define only one of
46、 several factors contributing to the dynamic properties of vehicles. Care shall be taken to keep test conditions between test runs as constant as possible. Therefore, it is recommended to limit weight changes caused by fuel consumption. 9.3 Warm-up The warm-up procedures specified in 6.1 of ISO 1503
47、7-1:2006 shall apply. 9.4 Test speed The test speed is defined as the nominal value of the longitudinal velocity. The standard test speed is 100 km/h. Other test speeds of interest may be used (preferably in 20 km/h steps). 10 Step input 10.1 Test procedure Drive the vehicle at the test speed (see 9
48、.4) in a straight line. The initial speed shall not deviate by more than 2 km/h from the test speed. Starting from a 0 /s 0,5 /s yaw velocity equilibrium condition, apply a steering input as rapidly as possible to a preselected value and maintain at that value for several seconds after the measured
49、vehicle motion variables have reached a steady state. In order to keep the steering input short relative to the vehicle response time, the time between 10 % and 90 % of the steering input should not be greater than 0,15 s. No change in throttle position shall be made, although speed may decrease. A steering-wheel stop may be used for selecting the input angle. Take data for both left and right turns. All data shall be taken in one direction followed by al
