Research On Virtual Roadway Test System And Evaluation Method For Vehicle Ride Comfort Based On New Test Regulation

Vehicle ride comfort which is widely concerned by designers and users responds thecomfort of passengers and integrity of goods when it’s running. The test regulation ofvehicle ride comfort random input is revised in2009at home. The influence of angularvelocity on the top of seat is not considered in this test regulation compared with the testregulation abroad. The specific requirements of data acquisition and processing are notclear in the test regulations at home and abroad, so that there are no unified referenceswhen in actual processing. Besides, the test system of vehicle ride comfort at home has lowintegration, poor reliability and single function. This paper outspreads the study in focusingon the two topics of evaluation method and the building of test system depending on theapplication. The main contents are listed as follows.(1) The hardware test system was built based on CAN bus. The ICP sensor whichcould measure three axial of linear acceleration was used to measure acceleration of nineaxial in three measuring points. The angular velocity of three axial on the top of seat wasmeasured by VN100sensor. The vehicle velocity and track were measured with GPS speedsensor of VBOX. The acceleration signal was gathered by Imtron data collector and wasuploaded to the host computer by TCP. Similarly, the angular velocity and vehicle velocitywere transmitted to the host computer by serial and CAN. All of the sensors were smalland easy to install.(2) The system test software was designed by LabVIEW. The status machine andqueue, which could ensure complete data transfer and recording and reliable operation ofthe software which could control data acquisition real time, playback data and generatereports, was used to transmit data between different modules. The entire software whichwas running on the host computer was easy to maintain by modularized design and thefunctions of software was easy to expand.(3) A comparative analysis of four test regulations, including ISO, GB/T, BS and VDIwas taken. The measurement of angular velocity signal on the top of seat was abandoned inthe GB/T test regulation. The impact on total weighted root-mean-square acceleration ofangular velocity was quantitatively analyzed by the test data. The analysis showed that theimpact on total weighted root-mean-square acceleration of angular velocity reached to15-20%when the vehicle velocity was in the range of50-70km/h in random input test andthe value of impact grew with vehicle velocity. Besides, the evaluation of vehicle ride comfort was focused on the case of little road excitation in test regulation. There was nospecific evaluation method in the case of strong road excitation.(4) Since there was no specific calculation method of weighted root-mean-squareacceleration of single axial in test regulation, it could be calculated by time or frequencydomain method. The simulation test showed that the result in time domain was20%largerthan that in frequency domain when the input signal was identical and the differentcalculation methods of auto spectral density function had an important impact on theresults in frequency domain. In view of this, this paper proposes that the sampling method,the design of time filters and the calculation method of auto spectral density function ofacceleration in frequency domain should be clearly defined to avoid the blindness of datasampling and processing.