Implementing B-Spline Path Planning Method Based on Roundabout Geometry Elements

This paper presents a parametric B-spline-based path planning approach for roundabout exit traverse planners to handle successively generated trajectories. A roundabout is a complex driving scene because of its large curvature and the varying intersection leg angles. A few studies focus on the relationship between roundabout intersection leg angle and path performance. This paper discusses B-spline advantages to curve road conditions and the impact of roundabout geometry elements on path planning performance. Knot vectors are defined, and control points are calculated to meet the requirements for generating paths that fit in different roundabout direction maneuvers. Four countries' roundabout design standards are summarized with their unique geometry elements. Additionally, the Stanley tracking controller was used to calculate the steering behavior. The impacts of maneuver directions and intersection angles are discussed. It is explained stepwise how the maneuver system framework was built and what notable impacts the geometric structure of the roundabout has on the paths.