Test Technologies Contributing to Electrification1. IntroductionFig. 1 View of DS2. New DS technology development2.1 Motion system improvementsFig. 2 DS system configuration*Customer Performance and Test Engineering Methodology Innovation DepartmentConsidering the increasing electrification of vehicles, a novel driving experience can be induced by finely controlling the highly responsive driving force. The flexibility of compliance can also be enhanced by increasing the number of control parameters and range of adjustment, which requires considerable effort and a longer compliance period when using an actual vehicle.Nissan Motors started the full-scale implementation of a driving simulator (DS, see Fig. 1) in 2019 and has since then employed it to test the safety of ProPILOT 2.0 (in the overriding mode) and the steering performance depending on the tire characteristics and vehicle specifications (e.g., height of the center of gravity and weight distribution). DS can evaluate the driving operation of general as well as highly skilled drivers, and therefore, it has recently been used to set new targets for driving experiences and complying with achievement levels based on the way people feel. To this end, reproducing the driving feeling more accurately is essential, and therefore, the DS motion system is being improved, and cueing control and other technologies are being developed to pursue more accurate reproductions. The details of the development of the DS technology and examples of applications that utilize its results are presented in this article.Nissan Motorsʼ DS includes long and short parallel rails, a hexapod, and a turntable to simulate real-time vehicle motion with one-to-one correspondence with a real vehicle (Fig. 2).The Y-parallel rails can generate a maximum acceleration of 12 m/s2 with an effective stroke of only ± 11 m before they are upgraded to ensure a safe stop at the maximum acceleration. However, in some cases, the DS system halted suddenly because of a shortage of effective strokes when performing various evaluations, such as acceleration sensation and control by electrification. In these cases, the feeling of acceleration was reduced by decreasing the gain in motion cueing or reducing the sensory time by using a filter. Some evaluation drivers commented that they felt a delay in motion in the DS evaluation compared to when using an actual vehicle, which implies that the system did not provide sufficient performance.As a measure of improvement, the control method of the Y-parallel rails was revised to increase the effective stroke from ± 11 m to ± 14 m, which extends the effective distance by 6 m; further, the servo characteristics were changed to improve the response of the XY-parallel unit, hexapod, and turn table. These revisions improve the response by up to 344% compared with the conventional time constant for the Y-parallel rails.392. Driving Simulator Test Technologies for Establishing Unique Performances of Electric VehiclesHiromi Fujita* Youichi Isono* Masayuki Imamura*Naoya Machida* Yutaka Hayashi*
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