Chassis Global Dynamics-Oriented Trajectory Planning for Automated Vehicles

The trajectory planning module generates optimal collision-free paths, which is essential to automated driving. Existing approaches have focused on traffic flow situations and the geometrical feasibility of local trajectories. However, high nonlinearity of vehicle dynamics could cause handling instability or even severe accidents in cases of tracking dynamic infeasible paths. Meanwhile, the variety and complexity of driving environments bring intractable challenges to safe trajectory planning. This article aims to address this crucial issue and proposes a chassis global dynamics-oriented trajectory planning scheme. This work designs comprehensive performance indices to represent handling dynamic status based on chassis dynamics modeling. As the basis of trajectory planning, a reference path is extracted from global digital map data, and the curvilinear coordinate frame is exploited. Numerical optimization is proposed to solve the trajectory planning problem. Thus, an optimal and dynamically feasible trajectory, which satisfies geometrical smoothness, chassis global dynamics indices, and feasible safety, can be generated and transformed. Various scenarios are involved in carrying out simulation tests, and those results demonstrate the excellent capability and effectiveness of the proposed scheme to provide optimal trajectories in a variety of driving situations.

I. Introduction

Nowadays, automated vehicle (AV) technologies have attracted extensive interest, and many researchers have devoted themselves to studying crucial issues on the path to AVs’ large-scale release and deployment [1], [2]. AVs mainly consist of the environment perception, decision-making module, trajectory planning module, and chassis execution module [3], [4], [5]. Each subsystem plays an essential role in safety-critical automated driving, and one of the most crucial steps is to plan proper collision-free trajectories for chassis actuators to track [6], [7]. However, real-world traffic scenes are difficult to deal with, and changeable traffic objects, various road geometry, and nonlinear vehicle dynamics responses cause sticky challenges to the trajectory planning module.