A Study on the Repeatability of Vehicle Ride Performance Measurements

Across the automotive industries, objective measurements and subjective assessment of vehicle ride performance are routinely carried out during development as well as validation phase. Objective measurements are receiving increased attention as they are generally believed to offer a higher degree of objectivity and repeatability compared to the subjective assessment alone. Typical industry practices include the acquisition of vehicle-occupant vibrational response on specified road sections, test surfaces on proving grounds or in a controlled input environment such as four-poster test rig. In presented work, a study is performed on the repeatability of vehicle ride performance metrics such as weighted RMS acceleration and frequency responses using the data acquired in repeated trials conducted using three different sports utility vehicles (SUVs) on a sufficiently long designated road section. Intra-vehicle and inter-vehicle ride performances are compared and studied against the mentioned metrics. Results indicate a significant variability of results in repeated trials, which in few cases is found to exceed the variation across the vehicles. These variabilities can be arguably attributed to several inevitable practical constraints such as vehicle speed variation, non-uniformity of lateral road cross-sections, etc. Further, the consistency of the results obtained using four-poster based measurements is studied and compared against the road-measurement based counterpart. Paper concludes with a suggestion to use simulated road profiles on four-poster test rig for objective vehicle ride performance measurements.