An Efficient Minimum-Time Trajectory Generation Strategy for Two-Track Car Vehicles

• Published in: IEEE transactions on control systems technology Vol. 23; no. 4; pp. 1505 - 1519
• Main Authors: Rucco, Alessandro, Notarstefano, Giuseppe, Hauser, John
• Format: Journal Article
• Language: English
• Published: IEEE 01.07.2015
• Subjects: Computational modeling; Force; Load modeling; Minimum-time; nonlinear optimal control; race car; Tires; Trajectory; trajectory optimization; two-track; Vehicle dynamics; Vehicles; two-track; vehicle dynamics; Minimum-time; trajectory optimization; race car; nonlinear optimal control
• ISSN: 1063-6536; 1558-0865
• DOI: 10.1109/TCST.2014.2377777

In this paper, we propose a novel approach to compute minimum-time trajectories for a two-track car model, including tires and (quasi-static) longitudinal and lateral load transfer. Given the car model and a planar track, including lane boundaries, our goal is to find a trajectory of the car minimizing the traveling time subject to steering and tire limits. Moreover, we enforce normal force constraints to avoid wheel liftoff. Based on a projection operator nonlinear optimal control technique, we propose a minimum-time trajectory generation strategy to compute the fastest car trajectory. Numerical computations are presented on two testing scenarios, a 90° turn and a real testing track. The computations allow us to both demonstrate the efficiency and accuracy of the proposed approach and highlight important features of the minimum-time trajectories. Finally, we integrate our strategy into a commercial vehicle dynamics software, thus computing minimum-time trajectories for a complex multibody vehicle model. The matching between the predicted trajectory and the one of the commercial toolbox further highlights the effectiveness of the proposed methodology.