12 Décembre – Thesis defense - Jean-Baptiste Receveur

09 h30 Amphi Jean-Paul Dom - Laboratory IMS / building A31 (Talence campus)

2D trajectory optimization: autonomous cars application.

Main concerns of this PHD thesis are the planning and optimization of a trajectory for autonomous vehicles. In the first chapter, main notions about trajectory or path planning are defined. A state of the art of the existing methods is presented, particularly oriented toward autonomous vehicles methods. From this state of the art is drawn a general planning structure, composed of a global (off-line) optimization algorithm and a local (on-line) reactive local method. The second chapter of this thesis focuses on a particular optimization criterium, the energetic cost of a trajectory, using an indirect method and the Pontryagin's maximum principle. This method gives an optimal longitudinal speed reference function of initial and final conditions, along with external forces. Then, in the third chapter, the global optimization method using a Genetic Algorithm (GA) is described. This method generates optimal passage points linked through a continuous curve composed of polynomials. The optimization uses five criteria, not necessarily linear, and fit to a particular distance corresponding to tasks usually handled by the human driver. Obtained optimal trajectories in chapter three are used in chapter four as a reference for the reactive trajectory control method using Potential Fields (PF). The defined GA-PF method is interesting in terms of optimization, anticipation, and reactivity. Finally, in the last chapter, the GA-PF method trajectory is injected in a trajectory tracking loop of a complex model of the vehicle horizontal dynamics. A bicycle model is inverted to create a relevant feedforward. Two feedback loops are used: a robust longitudinal control loop and a non-linear lateral control loop. Simulation results are presented in all the chapters, on road scenarios, with mobile obstacles, and in the end a possible extension to a 3D system.

Event localization