Implications of path tolerance and path characteristics on critical vehicle manoeuvres

ABSTRACT

Path planning and path following are core components in safe autonomous driving. Typically, a path planner provides a path with some tolerance on how tightly the path should be followed. Based on that, and other path characteristics, for example, sharpness of curves, a speed profile needs to be assigned so that the vehicle can stay within the given tolerance without going unnecessarily slow. Here, such trajectory planning is based on optimal control formulations where critical cases arise as on-the-limit solutions. The study focuses on heavy commercial vehicles, causing rollover to be of a major concern, due to the relatively high centre of gravity. Several results are obtained on required model complexity depending on path characteristics, for example, quantification of required path tolerance for a simple model to be sufficient, quantification of when yaw inertia needs to be considered in more detail, and how the curvature rate of change interplays with available friction. Overall, in situations where the vehicle is subject to a wide range of driving conditions, from good transport roads to more tricky avoidance manoeuvres, the requirements on the path following will vary. For this, the provided results form a basis for real-time path following.

KEYWORDS:

• Clothiod curve
• double lane change
• rollover
• optimal control
• vehicle dynamics
• path following

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The research presented in this paper has been supported by the iQMatic project funded by the innovation and research programme FFI/VINNOVA, the Strategic Area for ICT research ELLIIT funded by the Swedish Government within the Linnaeus Center CADICS, and the Swedish Research Council.