Objectification methods for ride comfort: Comparison of conventional methods and proposal of a new method for automated driving conditions

For efficient suspension development, objective performance indicators are needed which quantify the system with regard to ride comfort. This paper aims to investigate the capabilities of objectification methods from literature and presents a new method for automated and autonomous driving situations. Two studies were conducted in order to investigate objectification methods for ride comfort. In the first study, different objectification methods from literature were tested and compared. Sixteen subjects drove on a country road with a BMW 650i (F06). The subjects had to rate different damper settings which were tested at the same road section. The sensor data was evaluated according to ISO-2631:1997 [29] (equal to VDI- 2057:2017 [69]), BS 6841:1987 [7], as well as according to the methods of Rericha [60], Cucuz [13], Klingner [32] and Hennecke [28]. As subjective ratings imply ordinally scaled data sets, the correlation between the objective values and the subjective ratings is tested with the rank-correlation coefficient Kendalls-Tau and exploratory statistical methods. In the second study, forty participants drove and were driven around country roads in a BMW 135i (F20). The inattentive occupants had to perform an activity on a tablet which distracted them from the current driving situation. The subjects had to rate the ride comfort on four different road sections. Measurements have been conducted with a self-developed body measurement system and a seat pad sensor according to ISO-10326 [30]. The measurements and subjective ratings were correlated and statistically analyzed. The results of the first study show that the ISO-2631 [29], VDI-2057 and BS6841:1987 [7] perform best under the given test conditions. The method of Klingner [32] shows the best results of the non-standardized methods. The results of the second study show a significant difference in comfort perception between attentive and inattentive occupants. It can also be seen that inattentive occupants show higher values of RMS accelerations measured at the head, which is also visible in the vehicle to head transmissibility.