ISO 22140-2021 pdf free download – Passenger cars — Validation of vehicle dynamics simulation — Lateral transient response test methods.
Open-loop test methods specified in ISO 7401 are used to determine the lateral transient response ofpassenger cars in time and frequency domain as defined in ISO 3833.
In time domain:
– step input;
– sinusoidal input (one period).In frequency domain:
– random input;
pulse input;
continuous sinusoidal input.
The test characterizes transient response behaviour of a vehicle.Characteristic values and functions intime and frequency domains are considered necessary for characterizing vehicle transient response.Important characteristics in time domain are
– time lags between steering-wheel angle, lateral acceleration and yaw velocity,response times of lateral acceleration and yaw velocity,
lateral acceleration gain (lateral acceleration divided by steering-wheel angle),yaw velocity gain (yaw velocity divided by steering-wheel angle), and
-over-shoot values.
Important characteristics in frequency domain are the frequency responses,i.e.amplitudes and phasesof:
— lateral acceleration related to steering-wheel angle;-yaw velocity related to steering-wheel angle.
Within this document, the purpose of the test is to demonstrate that a vehicle simulation tool canpredict the vehicle behaviour within specified tolerances.A vehicle simulation tool is used to simulate aspecific existing vehicle running through the open-loop tests specified in ISO 7401.
The existing vehicle is physically tested at least three times to allow the test data to be compared withthe simulation results.
For time domain, response comparison is made between measured and simulated characteristic valuesusing tolerances of percent errors specified in this document.
For frequency domain, response comparison is made between measured and simulated characteristicfunctions of amplitudes and phases using tolerances specified in this document. Simulation resultsare used to define boundaries for frequency response curves, and the data from physical testing areoverlaid to see if the measurements fall within the acceptable ranges.
NOTE1 This document can be used for different purposes. Depending on the purpose of the validation, onlyparts of the validation requirements can be met.
NOTE2 Tolerance requirements can differ for applications, thus different tolerance values can be agreedbetween parties involved depending on the applications.
5Variables
The following variables shall be measured from physical testing, and applying the measured steering-wheel angle and longitudinal velocity as simulation input, yaw velocity and lateral acceleration arecomputed:
– steering-wheel angle,6pi- yaw velocity, vi ;
– lateral acceleration, ay;- longitudinal velocity,vx.
The following optional variables may be measured from physical testing， and obtained from asimulation tool:
– roll angle,g ;- sideslip angle,β;- lateral velocity, vy;
– steering-wheel torque, MH
6Simulation tool requirements6.1General
The simulation tool used to predict behaviour of a vehicle of interest shall include a mathematical modelcapable of calculating variables of interest (see Clause 5) for the test procedures being simulated.In thisdocument, the mathematical model is used to simulate an open-loop test series as specified in IS0 7401and provide calculated values of the characteristic variables and functions of interest.
The simulation tool shall be able to cover the lateral acceleration level of time domain tests wherelateral acceleration value starts from the nominal value of 4,0 m/s2.
The procedure for obtaining input data from experiments may differ for simulation tools,however,the input data shall not be manipulated for better correlation.Nonetheless, adaptation of input data toactual testing conditions such as road friction should be allowed.ISO 22140 pdf download.