ISO 22140:2021 pdf download – Passenger cars — Validation of vehicle dynamics simulation — Lateral transient response test methods.
4 Principle Open-loop test methods specified in ISO 7401 are used to determine the lateral transient response of passenger 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 in time 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 phases of: — 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 can predict the vehicle behaviour within specified tolerances. A vehicle simulation tool is used to simulate a specific 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 with the simulation results. For time domain, response comparison is made between measured and simulated characteristic values using tolerances of percent errors specified in this document. For frequency domain, response comparison is made between measured and simulated characteristic functions of amplitudes and phases using tolerances specified in this document. Simulation results are used to define boundaries for frequency response curves, and the data from physical testing are overlaid to see if the measurements fall within the acceptable ranges. NOTE 1 This document can be used for different purposes. Depending on the purpose of the validation, only parts of the validation requirements can be met. NOTE 2 Tolerance requirements can differ for applications, thus different tolerance values can be agreed between parties involved depending on the applications.