An example of a power-off maneuver of a vehicle without a straight line motion control

In this paper some selected results related to motor vehicle dynamics have been presented basing on the computer simulations of a sports two-seater performing a power-off straight line maneuver with different road conditions and the lack of a straight-line motion control having been included. All simulations have been performed in the MSC Adams/Car environment and the adopted maneuver was performed at the instant speed of 100km∙h-1. The selected phenomena have therefore been observed along the road long enough to relate them to different aspects of vehicle dynamics and the road traffic safety research. The adopted vehicle's model moved along the flat and the randomly uneven road with the almost similar and the almost different profiles for the left and the right wheels. Additionally, two values of the coefficient determining the maximum amplitude of road irregularities have been selected, i.e., 0.3 for the lower and 0.9 for the higher irregularities. This meant that the road conditions have been considered as one of the main factors possibly affecting disturbances of the motor vehicle's motion. Such research seems valuable from the point of view of the road safety and the vehicles' maintenance. A power-off straight maneuver is not very often performed during the normal road traffic and might seem useless. However, in this case it seemed essential to test the response of a vehicle's model to such factors as, e.g., the uneven loading, suspension characteristics, etc. This in turn might prove valuable when considering, e.g., the additional concentration of a driver to overcome the external disturbances acting on a moving vehicle. The presented research is the second part of the paper (Kisilowski, 2019) where the power-off maneuver was considered but with the straightforward motion control. Here, the straight-line control has been switched off to examine an untypical situation where, for example a driver loses consciousness, and the vehicle moves freely along the road. © 2021 Warsaw University of Technology. All rights reserved.