# Influence of the Road Model on the Optimal Maneuver of a Racing Motorcycle
## 6 Conclusions  
The influence of the road model on the optimal maneuver of the racing motorcycle has been studied. The essentials of the road reconstruction problem have been presented, as well as vehicle positioning on the 3D road and generalized QSS vehicle model. Three road models were constructed: the \"flat\" road model and two three-dimensional road models, reconstructed using elevation data from 1 m and 1 arc-second resolution digital elevation models. A 3D free-trajectory quasi-steady-state minimum lap time problem with experimentally bounded controls (jerks) was employed and compared in numerical examples to experimental data from the Supersport motorcycle used in the MotoAmerica championship. The use of digital elevation models is convenient, because it does not require any additional work to be done on the reconstructed track, nor does it (usually) incur additional costs. In general, DEMs can be divided according to the resolution of the data provided. The use of low-resolution global DEMs is encouraged by numerous free tools that automate the process of assigning elevation data to datasets containing geographic coordinates. Local DEMs require more user effort due to differences in file formats and reference systems used. Significant differences were found between road models of the Road Atlanta racetrack reconstructed using DEMs of different resolutions. Differences were particularly noticeable in the road camber angle and relative torsional curvature, while better agreement was observed in road inclination and normal curvature. The road model derived from the global DEM exhibited notable fluctuations in road geometry parameters, except for lane width and geodesic curvature, which were less dependent on elevation data. The comparative analysis between the computed optimal maneuvers and the experimental data showed that the results obtained from the track, reconstructed using the local DEM, closely matched the experimental data compared to two other road models. This agreement is particularly true for predicted corner speed, lateral acceleration extremes, and g-g diagram shape. The largest discrepancies in corner speed occurred in the simulation using the global DEM-based road model, exceeding those observed in the 2D case. The 1 arc-second resolution of the global DEM proved insufficient for accurate road camber identification. On tracks with significant variations in road geometry, such as the Road Atlanta racetrack analyzed, the \"flat\" road model provides limited information on vehicle motion. The maximum lateral acceleration is constant and depends only on the lateral friction coefficient. Both three-dimensional road models allowed better prediction of vehicle speed on inclined track segments, with superior results observed in the simulation using the local DEM road model. The total wheel load is greatly influenced by the road geometry as presented in the article. In the 2D simulation, the total vertical force acting on the wheels is also constant and equal to the product of the standard gravity and the sum of the vehicle and rider masses, while in the 3D simulations it is influenced by variations in the road's normal curvature. The total vertical load is higher when the vehicle travels through a valley bottom and lower when the vehicle travels over the crest of a hill. Both three-dimensional road models enabled the prediction of track segments with a high probability of front wheel lift resulting from normal curvature variations, which was consistent with suspension position and wheel speed measurements taken during actual vehicle motion. Again, the local DEM road model provided results closer to the measured ones. The last numerical example showed that the three-dimensional quasi-steady-state simulation on a detailed 3D road, in the presence of the experimentally limited controls (jerks), can be used to localize the track segments where the real rider actions can be improved.