STUDYING THE INFLUENCE OF ROLL AND PITCH DYNAMICS IN OPTIMAL ROAD-VEHICLE MANEUVERS
Kristoffer Lundahl,Karl Berntorp,Bj¨orn Olofsson,Jan Aslund and Lars Nielsen
∗ Department of Electrical Engineering,Link¨oping University SE–581 83 Link¨oping, Sweden,,
Department of Automatic Control,Lund University,SE–221 00 Lund, Sweden,
A comparative analysis shows how vehicle motion models of different complexity,capturing various characteristics,
influence the solution when used in time-critical optimal maneuvering problems. Vehicle models with combinations of roll and pitch dynamics as well as load transfer are considered,ranging from a single-track model to a double-track model with roll and pitch dynamics combined with load transfer.The optimal maneuvers in a 90◦-turn and a double lane-change scenario are formulated as minimum-time optimization problems,and are solved using numerical optimization software.The results obtained with the different models show that variables potentially important for safety systems, such as the yaw rate,slip angle, and geometric path, are qualitatively the same. Moreover, the numeric differences are mostly within a few percent. The results also indicate that although input torques differ about 50–100 % for certain parts of the maneuver between the most and least complex model considered, the resulting vehicle motions obtained are similar,irrespective of the model. Our main conclusion is that this enables the use of low-order models when designing the onboard optimization-based safety systems of the future.